Merge tag 'locking-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking and atomics updates from Thomas Gleixner:
 "The regular pile:

   - A few improvements to the mutex code

   - Documentation updates for atomics to clarify the difference between
     cmpxchg() and try_cmpxchg() and to explain the forward progress
     expectations.

   - Simplification of the atomics fallback generator

   - The addition of arch_atomic_long*() variants and generic arch_*()
     bitops based on them.

   - Add the missing might_sleep() invocations to the down*() operations
     of semaphores.

  The PREEMPT_RT locking core:

   - Scheduler updates to support the state preserving mechanism for
     'sleeping' spin- and rwlocks on RT.

     This mechanism is carefully preserving the state of the task when
     blocking on a 'sleeping' spin- or rwlock and takes regular wake-ups
     targeted at the same task into account. The preserved or updated
     (via a regular wakeup) state is restored when the lock has been
     acquired.

   - Restructuring of the rtmutex code so it can be utilized and
     extended for the RT specific lock variants.

   - Restructuring of the ww_mutex code to allow sharing of the ww_mutex
     specific functionality for rtmutex based ww_mutexes.

   - Header file disentangling to allow substitution of the regular lock
     implementations with the PREEMPT_RT variants without creating an
     unmaintainable #ifdef mess.

   - Shared base code for the PREEMPT_RT specific rw_semaphore and
     rwlock implementations.

     Contrary to the regular rw_semaphores and rwlocks the PREEMPT_RT
     implementation is writer unfair because it is infeasible to do
     priority inheritance on multiple readers. Experience over the years
     has shown that real-time workloads are not the typical workloads
     which are sensitive to writer starvation.

     The alternative solution would be to allow only a single reader
     which has been tried and discarded as it is a major bottleneck
     especially for mmap_sem. Aside of that many of the writer
     starvation critical usage sites have been converted to a writer
     side mutex/spinlock and RCU read side protections in the past
     decade so that the issue is less prominent than it used to be.

   - The actual rtmutex based lock substitutions for PREEMPT_RT enabled
     kernels which affect mutex, ww_mutex, rw_semaphore, spinlock_t and
     rwlock_t. The spin/rw_lock*() functions disable migration across
     the critical section to preserve the existing semantics vs per-CPU
     variables.

   - Rework of the futex REQUEUE_PI mechanism to handle the case of
     early wake-ups which interleave with a re-queue operation to
     prevent the situation that a task would be blocked on both the
     rtmutex associated to the outer futex and the rtmutex based hash
     bucket spinlock.

     While this situation cannot happen on !RT enabled kernels the
     changes make the underlying concurrency problems easier to
     understand in general. As a result the difference between !RT and
     RT kernels is reduced to the handling of waiting for the critical
     section. !RT kernels simply spin-wait as before and RT kernels
     utilize rcu_wait().

   - The substitution of local_lock for PREEMPT_RT with a spinlock which
     protects the critical section while staying preemptible. The CPU
     locality is established by disabling migration.

  The underlying concepts of this code have been in use in PREEMPT_RT for
  way more than a decade. The code has been refactored several times over
  the years and this final incarnation has been optimized once again to be
  as non-intrusive as possible, i.e. the RT specific parts are mostly
  isolated.

  It has been extensively tested in the 5.14-rt patch series and it has
  been verified that !RT kernels are not affected by these changes"

* tag 'locking-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (92 commits)
  locking/rtmutex: Return success on deadlock for ww_mutex waiters
  locking/rtmutex: Prevent spurious EDEADLK return caused by ww_mutexes
  locking/rtmutex: Dequeue waiter on ww_mutex deadlock
  locking/rtmutex: Dont dereference waiter lockless
  locking/semaphore: Add might_sleep() to down_*() family
  locking/ww_mutex: Initialize waiter.ww_ctx properly
  static_call: Update API documentation
  locking/local_lock: Add PREEMPT_RT support
  locking/spinlock/rt: Prepare for RT local_lock
  locking/rtmutex: Add adaptive spinwait mechanism
  locking/rtmutex: Implement equal priority lock stealing
  preempt: Adjust PREEMPT_LOCK_OFFSET for RT
  locking/rtmutex: Prevent lockdep false positive with PI futexes
  futex: Prevent requeue_pi() lock nesting issue on RT
  futex: Simplify handle_early_requeue_pi_wakeup()
  futex: Reorder sanity checks in futex_requeue()
  futex: Clarify comment in futex_requeue()
  futex: Restructure futex_requeue()
  futex: Correct the number of requeued waiters for PI
  futex: Remove bogus condition for requeue PI
  ...

16 files changed, 2648 insertions, 1175 deletions

diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 3572808223e4..d51cabf28f38 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -24,7 +24,8 @@ obj-$(CONFIG_SMP) += spinlock.o
 obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
-obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
+obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o
+obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o ww_rt_mutex.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index db9301591e3f..bc8abb8549d2 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -1,6 +1,4 @@
 /*
- * kernel/mutex-debug.c
- *
  * Debugging code for mutexes
  *
  * Started by Ingo Molnar:
@@ -22,7 +20,7 @@
 #include <linux/interrupt.h>
 #include <linux/debug_locks.h>
 
-#include "mutex-debug.h"
+#include "mutex.h"
 
 /*
  * Must be called with lock->wait_lock held.
@@ -32,6 +30,7 @@ void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
 	memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
 	waiter->magic = waiter;
 	INIT_LIST_HEAD(&waiter->list);
+	waiter->ww_ctx = MUTEX_POISON_WW_CTX;
 }
 
 void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h
deleted file mode 100644
index 53e631e1d76d..000000000000
--- a/kernel/locking/mutex-debug.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Mutexes: blocking mutual exclusion locks
- *
- * started by Ingo Molnar:
- *
- *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal declarations,
- * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
- * More details are in kernel/mutex-debug.c.
- */
-
-/*
- * This must be called with lock->wait_lock held.
- */
-extern void debug_mutex_lock_common(struct mutex *lock,
-				    struct mutex_waiter *waiter);
-extern void debug_mutex_wake_waiter(struct mutex *lock,
-				    struct mutex_waiter *waiter);
-extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
-extern void debug_mutex_add_waiter(struct mutex *lock,
-				   struct mutex_waiter *waiter,
-				   struct task_struct *task);
-extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
-				struct task_struct *task);
-extern void debug_mutex_unlock(struct mutex *lock);
-extern void debug_mutex_init(struct mutex *lock, const char *name,
-			     struct lock_class_key *key);
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index d2df5e68b503..d456579d0952 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -30,17 +30,20 @@
 #include <linux/debug_locks.h>
 #include <linux/osq_lock.h>
 
+#ifndef CONFIG_PREEMPT_RT
+#include "mutex.h"
+
 #ifdef CONFIG_DEBUG_MUTEXES
-# include "mutex-debug.h"
+# define MUTEX_WARN_ON(cond) DEBUG_LOCKS_WARN_ON(cond)
 #else
-# include "mutex.h"
+# define MUTEX_WARN_ON(cond)
 #endif
 
 void
 __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
 {
 	atomic_long_set(&lock->owner, 0);
-	spin_lock_init(&lock->wait_lock);
+	raw_spin_lock_init(&lock->wait_lock);
 	INIT_LIST_HEAD(&lock->wait_list);
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
 	osq_lock_init(&lock->osq);
@@ -91,55 +94,56 @@ static inline unsigned long __owner_flags(unsigned long owner)
 	return owner & MUTEX_FLAGS;
 }
 
-/*
- * Trylock variant that returns the owning task on failure.
- */
-static inline struct task_struct *__mutex_trylock_or_owner(struct mutex *lock)
+static inline struct task_struct *__mutex_trylock_common(struct mutex *lock, bool handoff)
 {
 	unsigned long owner, curr = (unsigned long)current;
 
 	owner = atomic_long_read(&lock->owner);
 	for (;;) { /* must loop, can race against a flag */
-		unsigned long old, flags = __owner_flags(owner);
+		unsigned long flags = __owner_flags(owner);
 		unsigned long task = owner & ~MUTEX_FLAGS;
 
 		if (task) {
-			if (likely(task != curr))
-				break;
-
-			if (likely(!(flags & MUTEX_FLAG_PICKUP)))
+			if (flags & MUTEX_FLAG_PICKUP) {
+				if (task != curr)
+					break;
+				flags &= ~MUTEX_FLAG_PICKUP;
+			} else if (handoff) {
+				if (flags & MUTEX_FLAG_HANDOFF)
+					break;
+				flags |= MUTEX_FLAG_HANDOFF;
+			} else {
 				break;
-
-			flags &= ~MUTEX_FLAG_PICKUP;
+			}
 		} else {
-#ifdef CONFIG_DEBUG_MUTEXES
-			DEBUG_LOCKS_WARN_ON(flags & MUTEX_FLAG_PICKUP);
-#endif
+			MUTEX_WARN_ON(flags & (MUTEX_FLAG_HANDOFF | MUTEX_FLAG_PICKUP));
+			task = curr;
 		}
 
-		/*
-		 * We set the HANDOFF bit, we must make sure it doesn't live
-		 * past the point where we acquire it. This would be possible
-		 * if we (accidentally) set the bit on an unlocked mutex.
-		 */
-		flags &= ~MUTEX_FLAG_HANDOFF;
-
-		old = atomic_long_cmpxchg_acquire(&lock->owner, owner, curr | flags);
-		if (old == owner)
-			return NULL;
-
-		owner = old;
+		if (atomic_long_try_cmpxchg_acquire(&lock->owner, &owner, task | flags)) {
+			if (task == curr)
+				return NULL;
+			break;
+		}
 	}
 
 	return __owner_task(owner);
 }
 
 /*
+ * Trylock or set HANDOFF
+ */
+static inline bool __mutex_trylock_or_handoff(struct mutex *lock, bool handoff)
+{
+	return !__mutex_trylock_common(lock, handoff);
+}
+
+/*
  * Actual trylock that will work on any unlocked state.
  */
 static inline bool __mutex_trylock(struct mutex *lock)
 {
-	return !__mutex_trylock_or_owner(lock);
+	return !__mutex_trylock_common(lock, false);
 }
 
 #ifndef CONFIG_DEBUG_LOCK_ALLOC
@@ -168,10 +172,7 @@ static __always_inline bool __mutex_unlock_fast(struct mutex *lock)
 {
 	unsigned long curr = (unsigned long)current;
 
-	if (atomic_long_cmpxchg_release(&lock->owner, curr, 0UL) == curr)
-		return true;
-
-	return false;
+	return atomic_long_try_cmpxchg_release(&lock->owner, &curr, 0UL);
 }
 #endif
 
@@ -226,23 +227,18 @@ static void __mutex_handoff(struct mutex *lock, struct task_struct *task)
 	unsigned long owner = atomic_long_read(&lock->owner);
 
 	for (;;) {
-		unsigned long old, new;
+		unsigned long new;
 
-#ifdef CONFIG_DEBUG_MUTEXES
-		DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current);
-		DEBUG_LOCKS_WARN_ON(owner & MUTEX_FLAG_PICKUP);
-#endif
+		MUTEX_WARN_ON(__owner_task(owner) != current);
+		MUTEX_WARN_ON(owner & MUTEX_FLAG_PICKUP);
 
 		new = (owner & MUTEX_FLAG_WAITERS);
 		new |= (unsigned long)task;
 		if (task)
 			new |= MUTEX_FLAG_PICKUP;
 
-		old = atomic_long_cmpxchg_release(&lock->owner, owner, new);
-		if (old == owner)
+		if (atomic_long_try_cmpxchg_release(&lock->owner, &owner, new))
 			break;
-
-		owner = old;
 	}
 }
 
@@ -286,218 +282,18 @@ void __sched mutex_lock(struct mutex *lock)
 EXPORT_SYMBOL(mutex_lock);
 #endif
 
-/*
- * Wait-Die:
- *   The newer transactions are killed when:
- *     It (the new transaction) makes a request for a lock being held
- *     by an older transaction.
- *
- * Wound-Wait:
- *   The newer transactions are wounded when:
- *     An older transaction makes a request for a lock being held by
- *     the newer transaction.
- */
-
-/*
- * Associate the ww_mutex @ww with the context @ww_ctx under which we acquired
- * it.
- */
-static __always_inline void
-ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
-	/*
-	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
-	 * but released with a normal mutex_unlock in this call.
-	 *
-	 * This should never happen, always use ww_mutex_unlock.
-	 */
-	DEBUG_LOCKS_WARN_ON(ww->ctx);
-
-	/*
-	 * Not quite done after calling ww_acquire_done() ?
-	 */
-	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+#include "ww_mutex.h"
 
-	if (ww_ctx->contending_lock) {
-		/*
-		 * After -EDEADLK you tried to
-		 * acquire a different ww_mutex? Bad!
-		 */
-		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
-
-		/*
-		 * You called ww_mutex_lock after receiving -EDEADLK,
-		 * but 'forgot' to unlock everything else first?
-		 */
-		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
-		ww_ctx->contending_lock = NULL;
-	}
-
-	/*
-	 * Naughty, using a different class will lead to undefined behavior!
-	 */
-	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
-#endif
-	ww_ctx->acquired++;
-	ww->ctx = ww_ctx;
-}
-
-/*
- * Determine if context @a is 'after' context @b. IOW, @a is a younger
- * transaction than @b and depending on algorithm either needs to wait for
- * @b or die.
- */
-static inline bool __sched
-__ww_ctx_stamp_after(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b)
-{
-
-	return (signed long)(a->stamp - b->stamp) > 0;
-}
-
-/*
- * Wait-Die; wake a younger waiter context (when locks held) such that it can
- * die.
- *
- * Among waiters with context, only the first one can have other locks acquired
- * already (ctx->acquired > 0), because __ww_mutex_add_waiter() and
- * __ww_mutex_check_kill() wake any but the earliest context.
- */
-static bool __sched
-__ww_mutex_die(struct mutex *lock, struct mutex_waiter *waiter,
-	       struct ww_acquire_ctx *ww_ctx)
-{
-	if (!ww_ctx->is_wait_die)
-		return false;
-
-	if (waiter->ww_ctx->acquired > 0 &&
-			__ww_ctx_stamp_after(waiter->ww_ctx, ww_ctx)) {
-		debug_mutex_wake_waiter(lock, waiter);
-		wake_up_process(waiter->task);
-	}
-
-	return true;
-}
-
-/*
- * Wound-Wait; wound a younger @hold_ctx if it holds the lock.
- *
- * Wound the lock holder if there are waiters with older transactions than
- * the lock holders. Even if multiple waiters may wound the lock holder,
- * it's sufficient that only one does.
- */
-static bool __ww_mutex_wound(struct mutex *lock,
-			     struct ww_acquire_ctx *ww_ctx,
-			     struct ww_acquire_ctx *hold_ctx)
-{
-	struct task_struct *owner = __mutex_owner(lock);
-
-	lockdep_assert_held(&lock->wait_lock);
-
-	/*
-	 * Possible through __ww_mutex_add_waiter() when we race with
-	 * ww_mutex_set_context_fastpath(). In that case we'll get here again
-	 * through __ww_mutex_check_waiters().
-	 */
-	if (!hold_ctx)
-		return false;
-
-	/*
-	 * Can have !owner because of __mutex_unlock_slowpath(), but if owner,
-	 * it cannot go away because we'll have FLAG_WAITERS set and hold
-	 * wait_lock.
-	 */
-	if (!owner)
-		return false;
-
-	if (ww_ctx->acquired > 0 && __ww_ctx_stamp_after(hold_ctx, ww_ctx)) {
-		hold_ctx->wounded = 1;
-
-		/*
-		 * wake_up_process() paired with set_current_state()
-		 * inserts sufficient barriers to make sure @owner either sees
-		 * it's wounded in __ww_mutex_check_kill() or has a
-		 * wakeup pending to re-read the wounded state.
-		 */
-		if (owner != current)
-			wake_up_process(owner);
-
-		return true;
-	}
-
-	return false;
-}
-
-/*
- * We just acquired @lock under @ww_ctx, if there are later contexts waiting
- * behind us on the wait-list, check if they need to die, or wound us.
- *
- * See __ww_mutex_add_waiter() for the list-order construction; basically the
- * list is ordered by stamp, smallest (oldest) first.
- *
- * This relies on never mixing wait-die/wound-wait on the same wait-list;
- * which is currently ensured by that being a ww_class property.
- *
- * The current task must not be on the wait list.
- */
-static void __sched
-__ww_mutex_check_waiters(struct mutex *lock, struct ww_acquire_ctx *ww_ctx)
-{
-	struct mutex_waiter *cur;
-
-	lockdep_assert_held(&lock->wait_lock);
-
-	list_for_each_entry(cur, &lock->wait_list, list) {
-		if (!cur->ww_ctx)
-			continue;
-
-		if (__ww_mutex_die(lock, cur, ww_ctx) ||
-		    __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx))
-			break;
-	}
-}
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
 
 /*
- * After acquiring lock with fastpath, where we do not hold wait_lock, set ctx
- * and wake up any waiters so they can recheck.
+ * Trylock variant that returns the owning task on failure.
  */
-static __always_inline void
-ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+static inline struct task_struct *__mutex_trylock_or_owner(struct mutex *lock)
 {
-	ww_mutex_lock_acquired(lock, ctx);
-
-	/*
-	 * The lock->ctx update should be visible on all cores before
-	 * the WAITERS check is done, otherwise contended waiters might be
-	 * missed. The contended waiters will either see ww_ctx == NULL
-	 * and keep spinning, or it will acquire wait_lock, add itself
-	 * to waiter list and sleep.
-	 */
-	smp_mb(); /* See comments above and below. */
-
-	/*
-	 * [W] ww->ctx = ctx	    [W] MUTEX_FLAG_WAITERS
-	 *     MB		        MB
-	 * [R] MUTEX_FLAG_WAITERS   [R] ww->ctx
-	 *
-	 * The memory barrier above pairs with the memory barrier in
-	 * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx
-	 * and/or !empty list.
-	 */
-	if (likely(!(atomic_long_read(&lock->base.owner) & MUTEX_FLAG_WAITERS)))
-		return;
-
-	/*
-	 * Uh oh, we raced in fastpath, check if any of the waiters need to
-	 * die or wound us.
-	 */
-	spin_lock(&lock->base.wait_lock);
-	__ww_mutex_check_waiters(&lock->base, ctx);
-	spin_unlock(&lock->base.wait_lock);
+	return __mutex_trylock_common(lock, false);
 }
 
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-
 static inline
 bool ww_mutex_spin_on_owner(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
 			    struct mutex_waiter *waiter)
@@ -754,171 +550,11 @@ EXPORT_SYMBOL(mutex_unlock);
  */
 void __sched ww_mutex_unlock(struct ww_mutex *lock)
 {
-	/*
-	 * The unlocking fastpath is the 0->1 transition from 'locked'
-	 * into 'unlocked' state:
-	 */
-	if (lock->ctx) {
-#ifdef CONFIG_DEBUG_MUTEXES
-		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
-#endif
-		if (lock->ctx->acquired > 0)
-			lock->ctx->acquired--;
-		lock->ctx = NULL;
-	}
-
+	__ww_mutex_unlock(lock);
 	mutex_unlock(&lock->base);
 }
 EXPORT_SYMBOL(ww_mutex_unlock);
 
-
-static __always_inline int __sched
-__ww_mutex_kill(struct mutex *lock, struct ww_acquire_ctx *ww_ctx)
-{
-	if (ww_ctx->acquired > 0) {
-#ifdef CONFIG_DEBUG_MUTEXES
-		struct ww_mutex *ww;
-
-		ww = container_of(lock, struct ww_mutex, base);
-		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock);
-		ww_ctx->contending_lock = ww;
-#endif
-		return -EDEADLK;
-	}
-
-	return 0;
-}
-
-
-/*
- * Check the wound condition for the current lock acquire.
- *
- * Wound-Wait: If we're wounded, kill ourself.
- *
- * Wait-Die: If we're trying to acquire a lock already held by an older
- *           context, kill ourselves.
- *
- * Since __ww_mutex_add_waiter() orders the wait-list on stamp, we only have to
- * look at waiters before us in the wait-list.
- */
-static inline int __sched
-__ww_mutex_check_kill(struct mutex *lock, struct mutex_waiter *waiter,
-		      struct ww_acquire_ctx *ctx)
-{
-	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
-	struct mutex_waiter *cur;
-
-	if (ctx->acquired == 0)
-		return 0;
-
-	if (!ctx->is_wait_die) {
-		if (ctx->wounded)
-			return __ww_mutex_kill(lock, ctx);
-
-		return 0;
-	}
-
-	if (hold_ctx && __ww_ctx_stamp_after(ctx, hold_ctx))
-		return __ww_mutex_kill(lock, ctx);
-
-	/*
-	 * If there is a waiter in front of us that has a context, then its
-	 * stamp is earlier than ours and we must kill ourself.
-	 */
-	cur = waiter;
-	list_for_each_entry_continue_reverse(cur, &lock->wait_list, list) {
-		if (!cur->ww_ctx)
-			continue;
-
-		return __ww_mutex_kill(lock, ctx);
-	}
-
-	return 0;
-}
-
-/*
- * Add @waiter to the wait-list, keep the wait-list ordered by stamp, smallest
- * first. Such that older contexts are preferred to acquire the lock over
- * younger contexts.
- *
- * Waiters without context are interspersed in FIFO order.
- *
- * Furthermore, for Wait-Die kill ourself immediately when possible (there are
- * older contexts already waiting) to avoid unnecessary waiting and for
- * Wound-Wait ensure we wound the owning context when it is younger.
- */
-static inline int __sched
-__ww_mutex_add_waiter(struct mutex_waiter *waiter,
-		      struct mutex *lock,
-		      struct ww_acquire_ctx *ww_ctx)
-{
-	struct mutex_waiter *cur;
-	struct list_head *pos;
-	bool is_wait_die;
-
-	if (!ww_ctx) {
-		__mutex_add_waiter(lock, waiter, &lock->wait_list);
-		return 0;
-	}
-
-	is_wait_die = ww_ctx->is_wait_die;
-
-	/*
-	 * Add the waiter before the first waiter with a higher stamp.
-	 * Waiters without a context are skipped to avoid starving
-	 * them. Wait-Die waiters may die here. Wound-Wait waiters
-	 * never die here, but they are sorted in stamp order and
-	 * may wound the lock holder.
-	 */
-	pos = &lock->wait_list;
-	list_for_each_entry_reverse(cur, &lock->wait_list, list) {
-		if (!cur->ww_ctx)
-			continue;
-
-		if (__ww_ctx_stamp_after(ww_ctx, cur->ww_ctx)) {
-			/*
-			 * Wait-Die: if we find an older context waiting, there
-			 * is no point in queueing behind it, as we'd have to
-			 * die the moment it would acquire the lock.
-			 */
-			if (is_wait_die) {
-				int ret = __ww_mutex_kill(lock, ww_ctx);
-
-				if (ret)
-					return ret;
-			}
-
-			break;
-		}
-
-		pos = &cur->list;
-
-		/* Wait-Die: ensure younger waiters die. */
-		__ww_mutex_die(lock, cur, ww_ctx);
-	}
-
-	__mutex_add_waiter(lock, waiter, pos);
-
-	/*
-	 * Wound-Wait: if we're blocking on a mutex owned by a younger context,
-	 * wound that such that we might proceed.
-	 */
-	if (!is_wait_die) {
-		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-
-		/*
-		 * See ww_mutex_set_context_fastpath(). Orders setting
-		 * MUTEX_FLAG_WAITERS vs the ww->ctx load,
-		 * such that either we or the fastpath will wound @ww->ctx.
-		 */
-		smp_mb();
-		__ww_mutex_wound(lock, ww_ctx, ww->ctx);
-	}
-
-	return 0;
-}
-
 /*
  * Lock a mutex (possibly interruptible), slowpath:
  */
@@ -928,7 +564,6 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		    struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
 {
 	struct mutex_waiter waiter;
-	bool first = false;
 	struct ww_mutex *ww;
 	int ret;
 
@@ -937,9 +572,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 
 	might_sleep();
 
-#ifdef CONFIG_DEBUG_MUTEXES
-	DEBUG_LOCKS_WARN_ON(lock->magic != lock);
-#endif
+	MUTEX_WARN_ON(lock->magic != lock);
 
 	ww = container_of(lock, struct ww_mutex, base);
 	if (ww_ctx) {
@@ -953,6 +586,10 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		 */
 		if (ww_ctx->acquired == 0)
 			ww_ctx->wounded = 0;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+		nest_lock = &ww_ctx->dep_map;
+#endif
 	}
 
 	preempt_disable();
@@ -968,7 +605,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		return 0;
 	}
 
-	spin_lock(&lock->wait_lock);
+	raw_spin_lock(&lock->wait_lock);
 	/*
 	 * After waiting to acquire the wait_lock, try again.
 	 */
@@ -980,17 +617,15 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 	}
 
 	debug_mutex_lock_common(lock, &waiter);
+	waiter.task = current;
+	if (use_ww_ctx)
+		waiter.ww_ctx = ww_ctx;
 
 	lock_contended(&lock->dep_map, ip);
 
 	if (!use_ww_ctx) {
 		/* add waiting tasks to the end of the waitqueue (FIFO): */
 		__mutex_add_waiter(lock, &waiter, &lock->wait_list);
-
-
-#ifdef CONFIG_DEBUG_MUTEXES
-		waiter.ww_ctx = MUTEX_POISON_WW_CTX;
-#endif
 	} else {
 		/*
 		 * Add in stamp order, waking up waiters that must kill
@@ -999,14 +634,12 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx);
 		if (ret)
 			goto err_early_kill;
-
-		waiter.ww_ctx = ww_ctx;
 	}
 
-	waiter.task = current;
-
 	set_current_state(state);
 	for (;;) {
+		bool first;
+
 		/*
 		 * Once we hold wait_lock, we're serialized against
 		 * mutex_unlock() handing the lock off to us, do a trylock
@@ -1032,18 +665,10 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 				goto err;
 		}
 
-		spin_unlock(&lock->wait_lock);
+		raw_spin_unlock(&lock->wait_lock);
 		schedule_preempt_disabled();
 
-		/*
-		 * ww_mutex needs to always recheck its position since its waiter
-		 * list is not FIFO ordered.
-		 */
-		if (ww_ctx || !first) {
-			first = __mutex_waiter_is_first(lock, &waiter);
-			if (first)
-				__mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
-		}
+		first = __mutex_waiter_is_first(lock, &waiter);
 
 		set_current_state(state);
 		/*
@@ -1051,13 +676,13 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		 * state back to RUNNING and fall through the next schedule(),
 		 * or we must see its unlock and acquire.
 		 */
-		if (__mutex_trylock(lock) ||
+		if (__mutex_trylock_or_handoff(lock, first) ||
 		    (first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
 			break;
 
-		spin_lock(&lock->wait_lock);
+		raw_spin_lock(&lock->wait_lock);
 	}
-	spin_lock(&lock->wait_lock);
+	raw_spin_lock(&lock->wait_lock);
 acquired:
 	__set_current_state(TASK_RUNNING);
 
@@ -1082,7 +707,7 @@ skip_wait:
 	if (ww_ctx)
 		ww_mutex_lock_acquired(ww, ww_ctx);
 
-	spin_unlock(&lock->wait_lock);
+	raw_spin_unlock(&lock->wait_lock);
 	preempt_enable();
 	return 0;
 
@@ -1090,7 +715,7 @@ err:
 	__set_current_state(TASK_RUNNING);
 	__mutex_remove_waiter(lock, &waiter);
 err_early_kill:
-	spin_unlock(&lock->wait_lock);
+	raw_spin_unlock(&lock->wait_lock);
 	debug_mutex_free_waiter(&waiter);
 	mutex_release(&lock->dep_map, ip);
 	preempt_enable();
@@ -1106,10 +731,9 @@ __mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass,
 
 static int __sched
 __ww_mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass,
-		struct lockdep_map *nest_lock, unsigned long ip,
-		struct ww_acquire_ctx *ww_ctx)
+		unsigned long ip, struct ww_acquire_ctx *ww_ctx)
 {
-	return __mutex_lock_common(lock, state, subclass, nest_lock, ip, ww_ctx, true);
+	return __mutex_lock_common(lock, state, subclass, NULL, ip, ww_ctx, true);
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -1189,8 +813,7 @@ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 
 	might_sleep();
 	ret =  __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE,
-			       0, ctx ? &ctx->dep_map : NULL, _RET_IP_,
-			       ctx);
+			       0, _RET_IP_, ctx);
 	if (!ret && ctx && ctx->acquired > 1)
 		return ww_mutex_deadlock_injection(lock, ctx);
 
@@ -1205,8 +828,7 @@ ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 
 	might_sleep();
 	ret = __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE,
-			      0, ctx ? &ctx->dep_map : NULL, _RET_IP_,
-			      ctx);
+			      0, _RET_IP_, ctx);
 
 	if (!ret && ctx && ctx->acquired > 1)
 		return ww_mutex_deadlock_injection(lock, ctx);
@@ -1237,29 +859,21 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
 	 */
 	owner = atomic_long_read(&lock->owner);
 	for (;;) {
-		unsigned long old;
-
-#ifdef CONFIG_DEBUG_MUTEXES
-		DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current);
-		DEBUG_LOCKS_WARN_ON(owner & MUTEX_FLAG_PICKUP);
-#endif
+		MUTEX_WARN_ON(__owner_task(owner) != current);
+		MUTEX_WARN_ON(owner & MUTEX_FLAG_PICKUP);
 
 		if (owner & MUTEX_FLAG_HANDOFF)
 			break;
 
-		old = atomic_long_cmpxchg_release(&lock->owner, owner,
-						  __owner_flags(owner));
-		if (old == owner) {
+		if (atomic_long_try_cmpxchg_release(&lock->owner, &owner, __owner_flags(owner))) {
 			if (owner & MUTEX_FLAG_WAITERS)
 				break;
 
 			return;
 		}
-
-		owner = old;
 	}
 
-	spin_lock(&lock->wait_lock);
+	raw_spin_lock(&lock->wait_lock);
 	debug_mutex_unlock(lock);
 	if (!list_empty(&lock->wait_list)) {
 		/* get the first entry from the wait-list: */
@@ -1276,7 +890,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
 	if (owner & MUTEX_FLAG_HANDOFF)
 		__mutex_handoff(lock, next);
 
-	spin_unlock(&lock->wait_lock);
+	raw_spin_unlock(&lock->wait_lock);
 
 	wake_up_q(&wake_q);
 }
@@ -1380,7 +994,7 @@ __mutex_lock_interruptible_slowpath(struct mutex *lock)
 static noinline int __sched
 __ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 {
-	return __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, 0, NULL,
+	return __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, 0,
 			       _RET_IP_, ctx);
 }
 
@@ -1388,7 +1002,7 @@ static noinline int __sched
 __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
 					    struct ww_acquire_ctx *ctx)
 {
-	return __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, 0, NULL,
+	return __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, 0,
 			       _RET_IP_, ctx);
 }
 
@@ -1412,9 +1026,7 @@ int __sched mutex_trylock(struct mutex *lock)
 {
 	bool locked;
 
-#ifdef CONFIG_DEBUG_MUTEXES
-	DEBUG_LOCKS_WARN_ON(lock->magic != lock);
-#endif
+	MUTEX_WARN_ON(lock->magic != lock);
 
 	locked = __mutex_trylock(lock);
 	if (locked)
@@ -1455,7 +1067,8 @@ ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 }
 EXPORT_SYMBOL(ww_mutex_lock_interruptible);
 
-#endif
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+#endif /* !CONFIG_PREEMPT_RT */
 
 /**
  * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index f0c710b1d192..0b2a79c4013b 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -5,19 +5,41 @@
  * started by Ingo Molnar:
  *
  *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal prototypes, for the
- * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
  */
 
-#define debug_mutex_wake_waiter(lock, waiter)		do { } while (0)
-#define debug_mutex_free_waiter(waiter)			do { } while (0)
-#define debug_mutex_add_waiter(lock, waiter, ti)	do { } while (0)
-#define debug_mutex_remove_waiter(lock, waiter, ti)     do { } while (0)
-#define debug_mutex_unlock(lock)			do { } while (0)
-#define debug_mutex_init(lock, name, key)		do { } while (0)
+/*
+ * This is the control structure for tasks blocked on mutex, which resides
+ * on the blocked task's kernel stack:
+ */
+struct mutex_waiter {
+	struct list_head	list;
+	struct task_struct	*task;
+	struct ww_acquire_ctx	*ww_ctx;
+#ifdef CONFIG_DEBUG_MUTEXES
+	void			*magic;
+#endif
+};
 
-static inline void
-debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
-{
-}
+#ifdef CONFIG_DEBUG_MUTEXES
+extern void debug_mutex_lock_common(struct mutex *lock,
+				    struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+				    struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+				   struct mutex_waiter *waiter,
+				   struct task_struct *task);
+extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+				      struct task_struct *task);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name,
+			     struct lock_class_key *key);
+#else /* CONFIG_DEBUG_MUTEXES */
+# define debug_mutex_lock_common(lock, waiter)		do { } while (0)
+# define debug_mutex_wake_waiter(lock, waiter)		do { } while (0)
+# define debug_mutex_free_waiter(waiter)		do { } while (0)
+# define debug_mutex_add_waiter(lock, waiter, ti)	do { } while (0)
+# define debug_mutex_remove_waiter(lock, waiter, ti)	do { } while (0)
+# define debug_mutex_unlock(lock)			do { } while (0)
+# define debug_mutex_init(lock, name, key)		do { } while (0)
+#endif /* !CONFIG_DEBUG_MUTEXES */
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index ad0db322ed3b..8eabdc79602b 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -8,20 +8,58 @@
  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
  *  Copyright (C) 2006 Esben Nielsen
+ * Adaptive Spinlocks:
+ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
+ *				     and Peter Morreale,
+ * Adaptive Spinlocks simplification:
+ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
  *
  *  See Documentation/locking/rt-mutex-design.rst for details.
  */
-#include <linux/spinlock.h>
-#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/deadline.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/rt.h>
-#include <linux/sched/deadline.h>
 #include <linux/sched/wake_q.h>
-#include <linux/sched/debug.h>
-#include <linux/timer.h>
+#include <linux/ww_mutex.h>
 
 #include "rtmutex_common.h"
 
+#ifndef WW_RT
+# define build_ww_mutex()	(false)
+# define ww_container_of(rtm)	NULL
+
+static inline int __ww_mutex_add_waiter(struct rt_mutex_waiter *waiter,
+					struct rt_mutex *lock,
+					struct ww_acquire_ctx *ww_ctx)
+{
+	return 0;
+}
+
+static inline void __ww_mutex_check_waiters(struct rt_mutex *lock,
+					    struct ww_acquire_ctx *ww_ctx)
+{
+}
+
+static inline void ww_mutex_lock_acquired(struct ww_mutex *lock,
+					  struct ww_acquire_ctx *ww_ctx)
+{
+}
+
+static inline int __ww_mutex_check_kill(struct rt_mutex *lock,
+					struct rt_mutex_waiter *waiter,
+					struct ww_acquire_ctx *ww_ctx)
+{
+	return 0;
+}
+
+#else
+# define build_ww_mutex()	(true)
+# define ww_container_of(rtm)	container_of(rtm, struct ww_mutex, base)
+# include "ww_mutex.h"
+#endif
+
 /*
  * lock->owner state tracking:
  *
@@ -50,7 +88,7 @@
  */
 
 static __always_inline void
-rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
+rt_mutex_set_owner(struct rt_mutex_base *lock, struct task_struct *owner)
 {
 	unsigned long val = (unsigned long)owner;
 
@@ -60,13 +98,13 @@ rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
 	WRITE_ONCE(lock->owner, (struct task_struct *)val);
 }
 
-static __always_inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void clear_rt_mutex_waiters(struct rt_mutex_base *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
-static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex_base *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -141,15 +179,26 @@ static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock)
  * set up.
  */
 #ifndef CONFIG_DEBUG_RT_MUTEXES
-# define rt_mutex_cmpxchg_acquire(l,c,n) (cmpxchg_acquire(&l->owner, c, n) == c)
-# define rt_mutex_cmpxchg_release(l,c,n) (cmpxchg_release(&l->owner, c, n) == c)
+static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return try_cmpxchg_acquire(&lock->owner, &old, new);
+}
+
+static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return try_cmpxchg_release(&lock->owner, &old, new);
+}
 
 /*
  * Callers must hold the ->wait_lock -- which is the whole purpose as we force
  * all future threads that attempt to [Rmw] the lock to the slowpath. As such
  * relaxed semantics suffice.
  */
-static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -165,7 +214,7 @@ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
  * 2) Drop lock->wait_lock
  * 3) Try to unlock the lock with cmpxchg
  */
-static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock,
 						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
@@ -201,10 +250,22 @@ static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
 }
 
 #else
-# define rt_mutex_cmpxchg_acquire(l,c,n)	(0)
-# define rt_mutex_cmpxchg_release(l,c,n)	(0)
+static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return false;
+
+}
 
-static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return false;
+}
+
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
@@ -213,7 +274,7 @@ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 /*
  * Simple slow path only version: lock->owner is protected by lock->wait_lock.
  */
-static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock,
 						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
@@ -223,11 +284,28 @@ static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
 }
 #endif
 
+static __always_inline int __waiter_prio(struct task_struct *task)
+{
+	int prio = task->prio;
+
+	if (!rt_prio(prio))
+		return DEFAULT_PRIO;
+
+	return prio;
+}
+
+static __always_inline void
+waiter_update_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+{
+	waiter->prio = __waiter_prio(task);
+	waiter->deadline = task->dl.deadline;
+}
+
 /*
  * Only use with rt_mutex_waiter_{less,equal}()
  */
 #define task_to_waiter(p)	\
-	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
+	&(struct rt_mutex_waiter){ .prio = __waiter_prio(p), .deadline = (p)->dl.deadline }
 
 static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left,
 						struct rt_mutex_waiter *right)
@@ -265,22 +343,63 @@ static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
 	return 1;
 }
 
+static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter,
+				  struct rt_mutex_waiter *top_waiter)
+{
+	if (rt_mutex_waiter_less(waiter, top_waiter))
+		return true;
+
+#ifdef RT_MUTEX_BUILD_SPINLOCKS
+	/*
+	 * Note that RT tasks are excluded from same priority (lateral)
+	 * steals to prevent the introduction of an unbounded latency.
+	 */
+	if (rt_prio(waiter->prio) || dl_prio(waiter->prio))
+		return false;
+
+	return rt_mutex_waiter_equal(waiter, top_waiter);
+#else
+	return false;
+#endif
+}
+
 #define __node_2_waiter(node) \
 	rb_entry((node), struct rt_mutex_waiter, tree_entry)
 
 static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
 {
-	return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b));
+	struct rt_mutex_waiter *aw = __node_2_waiter(a);
+	struct rt_mutex_waiter *bw = __node_2_waiter(b);
+
+	if (rt_mutex_waiter_less(aw, bw))
+		return 1;
+
+	if (!build_ww_mutex())
+		return 0;
+
+	if (rt_mutex_waiter_less(bw, aw))
+		return 0;
+
+	/* NOTE: relies on waiter->ww_ctx being set before insertion */
+	if (aw->ww_ctx) {
+		if (!bw->ww_ctx)
+			return 1;
+
+		return (signed long)(aw->ww_ctx->stamp -
+				     bw->ww_ctx->stamp) < 0;
+	}
+
+	return 0;
 }
 
 static __always_inline void
-rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
+rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
 {
 	rb_add_cached(&waiter->tree_entry, &lock->waiters, __waiter_less);
 }
 
 static __always_inline void
-rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
+rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
 {
 	if (RB_EMPTY_NODE(&waiter->tree_entry))
 		return;
@@ -326,6 +445,35 @@ static __always_inline void rt_mutex_adjust_prio(struct task_struct *p)
 	rt_mutex_setprio(p, pi_task);
 }
 
+/* RT mutex specific wake_q wrappers */
+static __always_inline void rt_mutex_wake_q_add(struct rt_wake_q_head *wqh,
+						struct rt_mutex_waiter *w)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && w->wake_state != TASK_NORMAL) {
+		if (IS_ENABLED(CONFIG_PROVE_LOCKING))
+			WARN_ON_ONCE(wqh->rtlock_task);
+		get_task_struct(w->task);
+		wqh->rtlock_task = w->task;
+	} else {
+		wake_q_add(&wqh->head, w->task);
+	}
+}
+
+static __always_inline void rt_mutex_wake_up_q(struct rt_wake_q_head *wqh)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && wqh->rtlock_task) {
+		wake_up_state(wqh->rtlock_task, TASK_RTLOCK_WAIT);
+		put_task_struct(wqh->rtlock_task);
+		wqh->rtlock_task = NULL;
+	}
+
+	if (!wake_q_empty(&wqh->head))
+		wake_up_q(&wqh->head);
+
+	/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
+	preempt_enable();
+}
+
 /*
  * Deadlock detection is conditional:
  *
@@ -348,12 +496,7 @@ rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 	return chwalk == RT_MUTEX_FULL_CHAINWALK;
 }
 
-/*
- * Max number of times we'll walk the boosting chain:
- */
-int max_lock_depth = 1024;
-
-static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+static __always_inline struct rt_mutex_base *task_blocked_on_lock(struct task_struct *p)
 {
 	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
 }
@@ -423,15 +566,15 @@ static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct
  */
 static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 					      enum rtmutex_chainwalk chwalk,
-					      struct rt_mutex *orig_lock,
-					      struct rt_mutex *next_lock,
+					      struct rt_mutex_base *orig_lock,
+					      struct rt_mutex_base *next_lock,
 					      struct rt_mutex_waiter *orig_waiter,
 					      struct task_struct *top_task)
 {
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
 	struct rt_mutex_waiter *prerequeue_top_waiter;
 	int ret = 0, depth = 0;
-	struct rt_mutex *lock;
+	struct rt_mutex_base *lock;
 	bool detect_deadlock;
 	bool requeue = true;
 
@@ -514,6 +657,31 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 		goto out_unlock_pi;
 
 	/*
+	 * There could be 'spurious' loops in the lock graph due to ww_mutex,
+	 * consider:
+	 *
+	 *   P1: A, ww_A, ww_B
+	 *   P2: ww_B, ww_A
+	 *   P3: A
+	 *
+	 * P3 should not return -EDEADLK because it gets trapped in the cycle
+	 * created by P1 and P2 (which will resolve -- and runs into
+	 * max_lock_depth above). Therefore disable detect_deadlock such that
+	 * the below termination condition can trigger once all relevant tasks
+	 * are boosted.
+	 *
+	 * Even when we start with ww_mutex we can disable deadlock detection,
+	 * since we would supress a ww_mutex induced deadlock at [6] anyway.
+	 * Supressing it here however is not sufficient since we might still
+	 * hit [6] due to adjustment driven iteration.
+	 *
+	 * NOTE: if someone were to create a deadlock between 2 ww_classes we'd
+	 * utterly fail to report it; lockdep should.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && waiter->ww_ctx && detect_deadlock)
+		detect_deadlock = false;
+
+	/*
 	 * Drop out, when the task has no waiters. Note,
 	 * top_waiter can be NULL, when we are in the deboosting
 	 * mode!
@@ -574,8 +742,21 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * walk, we detected a deadlock.
 	 */
 	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
-		raw_spin_unlock(&lock->wait_lock);
 		ret = -EDEADLK;
+
+		/*
+		 * When the deadlock is due to ww_mutex; also see above. Don't
+		 * report the deadlock and instead let the ww_mutex wound/die
+		 * logic pick which of the contending threads gets -EDEADLK.
+		 *
+		 * NOTE: assumes the cycle only contains a single ww_class; any
+		 * other configuration and we fail to report; also, see
+		 * lockdep.
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && orig_waiter->ww_ctx)
+			ret = 0;
+
+		raw_spin_unlock(&lock->wait_lock);
 		goto out_unlock_pi;
 	}
 
@@ -653,8 +834,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * serializes all pi_waiters access and rb_erase() does not care about
 	 * the values of the node being removed.
 	 */
-	waiter->prio = task->prio;
-	waiter->deadline = task->dl.deadline;
+	waiter_update_prio(waiter, task);
 
 	rt_mutex_enqueue(lock, waiter);
 
@@ -676,7 +856,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 		 * to get the lock.
 		 */
 		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
-			wake_up_process(rt_mutex_top_waiter(lock)->task);
+			wake_up_state(waiter->task, waiter->wake_state);
 		raw_spin_unlock_irq(&lock->wait_lock);
 		return 0;
 	}
@@ -779,7 +959,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
  *	    callsite called task_blocked_on_lock(), otherwise NULL
  */
 static int __sched
-try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+try_to_take_rt_mutex(struct rt_mutex_base *lock, struct task_struct *task,
 		     struct rt_mutex_waiter *waiter)
 {
 	lockdep_assert_held(&lock->wait_lock);
@@ -815,19 +995,21 @@ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 	 * trylock attempt.
 	 */
 	if (waiter) {
-		/*
-		 * If waiter is not the highest priority waiter of
-		 * @lock, give up.
-		 */
-		if (waiter != rt_mutex_top_waiter(lock))
-			return 0;
+		struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock);
 
 		/*
-		 * We can acquire the lock. Remove the waiter from the
-		 * lock waiters tree.
+		 * If waiter is the highest priority waiter of @lock,
+		 * or allowed to steal it, take it over.
 		 */
-		rt_mutex_dequeue(lock, waiter);
-
+		if (waiter == top_waiter || rt_mutex_steal(waiter, top_waiter)) {
+			/*
+			 * We can acquire the lock. Remove the waiter from the
+			 * lock waiters tree.
+			 */
+			rt_mutex_dequeue(lock, waiter);
+		} else {
+			return 0;
+		}
 	} else {
 		/*
 		 * If the lock has waiters already we check whether @task is
@@ -838,13 +1020,9 @@ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 		 * not need to be dequeued.
 		 */
 		if (rt_mutex_has_waiters(lock)) {
-			/*
-			 * If @task->prio is greater than or equal to
-			 * the top waiter priority (kernel view),
-			 * @task lost.
-			 */
-			if (!rt_mutex_waiter_less(task_to_waiter(task),
-						  rt_mutex_top_waiter(lock)))
+			/* Check whether the trylock can steal it. */
+			if (!rt_mutex_steal(task_to_waiter(task),
+					    rt_mutex_top_waiter(lock)))
 				return 0;
 
 			/*
@@ -897,14 +1075,15 @@ takeit:
  *
  * This must be called with lock->wait_lock held and interrupts disabled
  */
-static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
+static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
 					   struct rt_mutex_waiter *waiter,
 					   struct task_struct *task,
+					   struct ww_acquire_ctx *ww_ctx,
 					   enum rtmutex_chainwalk chwalk)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
 	struct rt_mutex_waiter *top_waiter = waiter;
-	struct rt_mutex *next_lock;
+	struct rt_mutex_base *next_lock;
 	int chain_walk = 0, res;
 
 	lockdep_assert_held(&lock->wait_lock);
@@ -924,8 +1103,7 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
 	raw_spin_lock(&task->pi_lock);
 	waiter->task = task;
 	waiter->lock = lock;
-	waiter->prio = task->prio;
-	waiter->deadline = task->dl.deadline;
+	waiter_update_prio(waiter, task);
 
 	/* Get the top priority waiter on the lock */
 	if (rt_mutex_has_waiters(lock))
@@ -936,6 +1114,21 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
 
 	raw_spin_unlock(&task->pi_lock);
 
+	if (build_ww_mutex() && ww_ctx) {
+		struct rt_mutex *rtm;
+
+		/* Check whether the waiter should back out immediately */
+		rtm = container_of(lock, struct rt_mutex, rtmutex);
+		res = __ww_mutex_add_waiter(waiter, rtm, ww_ctx);
+		if (res) {
+			raw_spin_lock(&task->pi_lock);
+			rt_mutex_dequeue(lock, waiter);
+			task->pi_blocked_on = NULL;
+			raw_spin_unlock(&task->pi_lock);
+			return res;
+		}
+	}
+
 	if (!owner)
 		return 0;
 
@@ -986,8 +1179,8 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
  *
  * Called with lock->wait_lock held and interrupts disabled.
  */
-static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q,
-					    struct rt_mutex *lock)
+static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh,
+					    struct rt_mutex_base *lock)
 {
 	struct rt_mutex_waiter *waiter;
 
@@ -1023,235 +1216,14 @@ static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q,
 	 * deboost but before waking our donor task, hence the preempt_disable()
 	 * before unlock.
 	 *
-	 * Pairs with preempt_enable() in rt_mutex_postunlock();
+	 * Pairs with preempt_enable() in rt_mutex_wake_up_q();
 	 */
 	preempt_disable();
-	wake_q_add(wake_q, waiter->task);
-	raw_spin_unlock(&current->pi_lock);
-}
-
-/*
- * Remove a waiter from a lock and give up
- *
- * Must be called with lock->wait_lock held and interrupts disabled. I must
- * have just failed to try_to_take_rt_mutex().
- */
-static void __sched remove_waiter(struct rt_mutex *lock,
-				  struct rt_mutex_waiter *waiter)
-{
-	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
-	struct task_struct *owner = rt_mutex_owner(lock);
-	struct rt_mutex *next_lock;
-
-	lockdep_assert_held(&lock->wait_lock);
-
-	raw_spin_lock(&current->pi_lock);
-	rt_mutex_dequeue(lock, waiter);
-	current->pi_blocked_on = NULL;
+	rt_mutex_wake_q_add(wqh, waiter);
 	raw_spin_unlock(&current->pi_lock);
-
-	/*
-	 * Only update priority if the waiter was the highest priority
-	 * waiter of the lock and there is an owner to update.
-	 */
-	if (!owner || !is_top_waiter)
-		return;
-
-	raw_spin_lock(&owner->pi_lock);
-
-	rt_mutex_dequeue_pi(owner, waiter);
-
-	if (rt_mutex_has_waiters(lock))
-		rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock));
-
-	rt_mutex_adjust_prio(owner);
-
-	/* Store the lock on which owner is blocked or NULL */
-	next_lock = task_blocked_on_lock(owner);
-
-	raw_spin_unlock(&owner->pi_lock);
-
-	/*
-	 * Don't walk the chain, if the owner task is not blocked
-	 * itself.
-	 */
-	if (!next_lock)
-		return;
-
-	/* gets dropped in rt_mutex_adjust_prio_chain()! */
-	get_task_struct(owner);
-
-	raw_spin_unlock_irq(&lock->wait_lock);
-
-	rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock,
-				   next_lock, NULL, current);
-
-	raw_spin_lock_irq(&lock->wait_lock);
-}
-
-/*
- * Recheck the pi chain, in case we got a priority setting
- *
- * Called from sched_setscheduler
- */
-void __sched rt_mutex_adjust_pi(struct task_struct *task)
-{
-	struct rt_mutex_waiter *waiter;
-	struct rt_mutex *next_lock;
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&task->pi_lock, flags);
-
-	waiter = task->pi_blocked_on;
-	if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
-		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-		return;
-	}
-	next_lock = waiter->lock;
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-
-	/* gets dropped in rt_mutex_adjust_prio_chain()! */
-	get_task_struct(task);
-
-	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
-				   next_lock, NULL, task);
 }
 
-void __sched rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
-{
-	debug_rt_mutex_init_waiter(waiter);
-	RB_CLEAR_NODE(&waiter->pi_tree_entry);
-	RB_CLEAR_NODE(&waiter->tree_entry);
-	waiter->task = NULL;
-}
-
-/**
- * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
- * @lock:		 the rt_mutex to take
- * @state:		 the state the task should block in (TASK_INTERRUPTIBLE
- *			 or TASK_UNINTERRUPTIBLE)
- * @timeout:		 the pre-initialized and started timer, or NULL for none
- * @waiter:		 the pre-initialized rt_mutex_waiter
- *
- * Must be called with lock->wait_lock held and interrupts disabled
- */
-static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state,
-				       struct hrtimer_sleeper *timeout,
-				       struct rt_mutex_waiter *waiter)
-{
-	int ret = 0;
-
-	for (;;) {
-		/* Try to acquire the lock: */
-		if (try_to_take_rt_mutex(lock, current, waiter))
-			break;
-
-		if (timeout && !timeout->task) {
-			ret = -ETIMEDOUT;
-			break;
-		}
-		if (signal_pending_state(state, current)) {
-			ret = -EINTR;
-			break;
-		}
-
-		raw_spin_unlock_irq(&lock->wait_lock);
-
-		schedule();
-
-		raw_spin_lock_irq(&lock->wait_lock);
-		set_current_state(state);
-	}
-
-	__set_current_state(TASK_RUNNING);
-	return ret;
-}
-
-static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
-					     struct rt_mutex_waiter *w)
-{
-	/*
-	 * If the result is not -EDEADLOCK or the caller requested
-	 * deadlock detection, nothing to do here.
-	 */
-	if (res != -EDEADLOCK || detect_deadlock)
-		return;
-
-	/*
-	 * Yell loudly and stop the task right here.
-	 */
-	WARN(1, "rtmutex deadlock detected\n");
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		schedule();
-	}
-}
-
-/*
- * Slow path lock function:
- */
-static int __sched rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state,
-				     struct hrtimer_sleeper *timeout,
-				     enum rtmutex_chainwalk chwalk)
-{
-	struct rt_mutex_waiter waiter;
-	unsigned long flags;
-	int ret = 0;
-
-	rt_mutex_init_waiter(&waiter);
-
-	/*
-	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
-	 * be called in early boot if the cmpxchg() fast path is disabled
-	 * (debug, no architecture support). In this case we will acquire the
-	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
-	 * enable interrupts in that early boot case. So we need to use the
-	 * irqsave/restore variants.
-	 */
-	raw_spin_lock_irqsave(&lock->wait_lock, flags);
-
-	/* Try to acquire the lock again: */
-	if (try_to_take_rt_mutex(lock, current, NULL)) {
-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-		return 0;
-	}
-
-	set_current_state(state);
-
-	/* Setup the timer, when timeout != NULL */
-	if (unlikely(timeout))
-		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
-
-	ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
-
-	if (likely(!ret))
-		/* sleep on the mutex */
-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
-
-	if (unlikely(ret)) {
-		__set_current_state(TASK_RUNNING);
-		remove_waiter(lock, &waiter);
-		rt_mutex_handle_deadlock(ret, chwalk, &waiter);
-	}
-
-	/*
-	 * try_to_take_rt_mutex() sets the waiter bit
-	 * unconditionally. We might have to fix that up.
-	 */
-	fixup_rt_mutex_waiters(lock);
-
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-
-	/* Remove pending timer: */
-	if (unlikely(timeout))
-		hrtimer_cancel(&timeout->timer);
-
-	debug_rt_mutex_free_waiter(&waiter);
-
-	return ret;
-}
-
-static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched __rt_mutex_slowtrylock(struct rt_mutex_base *lock)
 {
 	int ret = try_to_take_rt_mutex(lock, current, NULL);
 
@@ -1267,7 +1239,7 @@ static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock)
 /*
  * Slow path try-lock function:
  */
-static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched rt_mutex_slowtrylock(struct rt_mutex_base *lock)
 {
 	unsigned long flags;
 	int ret;
@@ -1293,25 +1265,20 @@ static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock)
 	return ret;
 }
 
-/*
- * Performs the wakeup of the top-waiter and re-enables preemption.
- */
-void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
+static __always_inline int __rt_mutex_trylock(struct rt_mutex_base *lock)
 {
-	wake_up_q(wake_q);
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return 1;
 
-	/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
-	preempt_enable();
+	return rt_mutex_slowtrylock(lock);
 }
 
 /*
  * Slow path to release a rt-mutex.
- *
- * Return whether the current task needs to call rt_mutex_postunlock().
  */
-static void __sched rt_mutex_slowunlock(struct rt_mutex *lock)
+static void __sched rt_mutex_slowunlock(struct rt_mutex_base *lock)
 {
-	DEFINE_WAKE_Q(wake_q);
+	DEFINE_RT_WAKE_Q(wqh);
 	unsigned long flags;
 
 	/* irqsave required to support early boot calls */
@@ -1364,422 +1331,387 @@ static void __sched rt_mutex_slowunlock(struct rt_mutex *lock)
 	 *
 	 * Queue the next waiter for wakeup once we release the wait_lock.
 	 */
-	mark_wakeup_next_waiter(&wake_q, lock);
+	mark_wakeup_next_waiter(&wqh, lock);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
-	rt_mutex_postunlock(&wake_q);
+	rt_mutex_wake_up_q(&wqh);
 }
 
-/*
- * debug aware fast / slowpath lock,trylock,unlock
- *
- * The atomic acquire/release ops are compiled away, when either the
- * architecture does not support cmpxchg or when debugging is enabled.
- */
-static __always_inline int __rt_mutex_lock(struct rt_mutex *lock, long state,
-					   unsigned int subclass)
+static __always_inline void __rt_mutex_unlock(struct rt_mutex_base *lock)
 {
-	int ret;
-
-	might_sleep();
-	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
-
-	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 0;
+	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+		return;
 
-	ret = rt_mutex_slowlock(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
-	if (ret)
-		mutex_release(&lock->dep_map, _RET_IP_);
-	return ret;
+	rt_mutex_slowunlock(lock);
 }
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-/**
- * rt_mutex_lock_nested - lock a rt_mutex
- *
- * @lock: the rt_mutex to be locked
- * @subclass: the lockdep subclass
- */
-void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+#ifdef CONFIG_SMP
+static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter,
+				  struct task_struct *owner)
 {
-	__rt_mutex_lock(lock, TASK_UNINTERRUPTIBLE, subclass);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
-
-#else /* !CONFIG_DEBUG_LOCK_ALLOC */
+	bool res = true;
 
-/**
- * rt_mutex_lock - lock a rt_mutex
- *
- * @lock: the rt_mutex to be locked
- */
-void __sched rt_mutex_lock(struct rt_mutex *lock)
+	rcu_read_lock();
+	for (;;) {
+		/* If owner changed, trylock again. */
+		if (owner != rt_mutex_owner(lock))
+			break;
+		/*
+		 * Ensure that @owner is dereferenced after checking that
+		 * the lock owner still matches @owner. If that fails,
+		 * @owner might point to freed memory. If it still matches,
+		 * the rcu_read_lock() ensures the memory stays valid.
+		 */
+		barrier();
+		/*
+		 * Stop spinning when:
+		 *  - the lock owner has been scheduled out
+		 *  - current is not longer the top waiter
+		 *  - current is requested to reschedule (redundant
+		 *    for CONFIG_PREEMPT_RCU=y)
+		 *  - the VCPU on which owner runs is preempted
+		 */
+		if (!owner->on_cpu || need_resched() ||
+		    rt_mutex_waiter_is_top_waiter(lock, waiter) ||
+		    vcpu_is_preempted(task_cpu(owner))) {
+			res = false;
+			break;
+		}
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return res;
+}
+#else
+static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter,
+				  struct task_struct *owner)
 {
-	__rt_mutex_lock(lock, TASK_UNINTERRUPTIBLE, 0);
+	return false;
 }
-EXPORT_SYMBOL_GPL(rt_mutex_lock);
 #endif
 
-/**
- * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
- *
- * @lock:		the rt_mutex to be locked
- *
- * Returns:
- *  0		on success
- * -EINTR	when interrupted by a signal
+#ifdef RT_MUTEX_BUILD_MUTEX
+/*
+ * Functions required for:
+ *	- rtmutex, futex on all kernels
+ *	- mutex and rwsem substitutions on RT kernels
  */
-int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
-{
-	return __rt_mutex_lock(lock, TASK_INTERRUPTIBLE, 0);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
-/**
- * rt_mutex_trylock - try to lock a rt_mutex
- *
- * @lock:	the rt_mutex to be locked
- *
- * This function can only be called in thread context. It's safe to call it
- * from atomic regions, but not from hard or soft interrupt context.
+/*
+ * Remove a waiter from a lock and give up
  *
- * Returns:
- *  1 on success
- *  0 on contention
+ * Must be called with lock->wait_lock held and interrupts disabled. It must
+ * have just failed to try_to_take_rt_mutex().
  */
-int __sched rt_mutex_trylock(struct rt_mutex *lock)
+static void __sched remove_waiter(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter)
 {
-	int ret;
+	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
+	struct task_struct *owner = rt_mutex_owner(lock);
+	struct rt_mutex_base *next_lock;
 
-	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
-		return 0;
+	lockdep_assert_held(&lock->wait_lock);
+
+	raw_spin_lock(&current->pi_lock);
+	rt_mutex_dequeue(lock, waiter);
+	current->pi_blocked_on = NULL;
+	raw_spin_unlock(&current->pi_lock);
 
 	/*
-	 * No lockdep annotation required because lockdep disables the fast
-	 * path.
+	 * Only update priority if the waiter was the highest priority
+	 * waiter of the lock and there is an owner to update.
 	 */
-	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 1;
-
-	ret = rt_mutex_slowtrylock(lock);
-	if (ret)
-		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(rt_mutex_trylock);
-
-/**
- * rt_mutex_unlock - unlock a rt_mutex
- *
- * @lock: the rt_mutex to be unlocked
- */
-void __sched rt_mutex_unlock(struct rt_mutex *lock)
-{
-	mutex_release(&lock->dep_map, _RET_IP_);
-	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+	if (!owner || !is_top_waiter)
 		return;
 
-	rt_mutex_slowunlock(lock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_unlock);
+	raw_spin_lock(&owner->pi_lock);
 
-/*
- * Futex variants, must not use fastpath.
- */
-int __sched rt_mutex_futex_trylock(struct rt_mutex *lock)
-{
-	return rt_mutex_slowtrylock(lock);
-}
+	rt_mutex_dequeue_pi(owner, waiter);
 
-int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
-{
-	return __rt_mutex_slowtrylock(lock);
-}
+	if (rt_mutex_has_waiters(lock))
+		rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock));
 
-/**
- * __rt_mutex_futex_unlock - Futex variant, that since futex variants
- * do not use the fast-path, can be simple and will not need to retry.
- *
- * @lock:	The rt_mutex to be unlocked
- * @wake_q:	The wake queue head from which to get the next lock waiter
- */
-bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				     struct wake_q_head *wake_q)
-{
-	lockdep_assert_held(&lock->wait_lock);
+	rt_mutex_adjust_prio(owner);
 
-	debug_rt_mutex_unlock(lock);
+	/* Store the lock on which owner is blocked or NULL */
+	next_lock = task_blocked_on_lock(owner);
 
-	if (!rt_mutex_has_waiters(lock)) {
-		lock->owner = NULL;
-		return false; /* done */
-	}
+	raw_spin_unlock(&owner->pi_lock);
 
 	/*
-	 * We've already deboosted, mark_wakeup_next_waiter() will
-	 * retain preempt_disabled when we drop the wait_lock, to
-	 * avoid inversion prior to the wakeup.  preempt_disable()
-	 * therein pairs with rt_mutex_postunlock().
+	 * Don't walk the chain, if the owner task is not blocked
+	 * itself.
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	if (!next_lock)
+		return;
 
-	return true; /* call postunlock() */
-}
+	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+	get_task_struct(owner);
 
-void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
-{
-	DEFINE_WAKE_Q(wake_q);
-	unsigned long flags;
-	bool postunlock;
+	raw_spin_unlock_irq(&lock->wait_lock);
 
-	raw_spin_lock_irqsave(&lock->wait_lock, flags);
-	postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock,
+				   next_lock, NULL, current);
 
-	if (postunlock)
-		rt_mutex_postunlock(&wake_q);
+	raw_spin_lock_irq(&lock->wait_lock);
 }
 
 /**
- * __rt_mutex_init - initialize the rt_mutex
- *
- * @lock:	The rt_mutex to be initialized
- * @name:	The lock name used for debugging
- * @key:	The lock class key used for debugging
- *
- * Initialize the rt_mutex to unlocked state.
+ * rt_mutex_slowlock_block() - Perform the wait-wake-try-to-take loop
+ * @lock:		 the rt_mutex to take
+ * @ww_ctx:		 WW mutex context pointer
+ * @state:		 the state the task should block in (TASK_INTERRUPTIBLE
+ *			 or TASK_UNINTERRUPTIBLE)
+ * @timeout:		 the pre-initialized and started timer, or NULL for none
+ * @waiter:		 the pre-initialized rt_mutex_waiter
  *
- * Initializing of a locked rt_mutex is not allowed
+ * Must be called with lock->wait_lock held and interrupts disabled
  */
-void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name,
-		     struct lock_class_key *key)
+static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock,
+					   struct ww_acquire_ctx *ww_ctx,
+					   unsigned int state,
+					   struct hrtimer_sleeper *timeout,
+					   struct rt_mutex_waiter *waiter)
 {
-	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-	lockdep_init_map(&lock->dep_map, name, key, 0);
+	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
+	struct task_struct *owner;
+	int ret = 0;
 
-	__rt_mutex_basic_init(lock);
-}
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
+	for (;;) {
+		/* Try to acquire the lock: */
+		if (try_to_take_rt_mutex(lock, current, waiter))
+			break;
 
-/**
- * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
- *				proxy owner
- *
- * @lock:	the rt_mutex to be locked
- * @proxy_owner:the task to set as owner
- *
- * No locking. Caller has to do serializing itself
- *
- * Special API call for PI-futex support. This initializes the rtmutex and
- * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not
- * possible at this point because the pi_state which contains the rtmutex
- * is not yet visible to other tasks.
- */
-void __sched rt_mutex_init_proxy_locked(struct rt_mutex *lock,
-					struct task_struct *proxy_owner)
-{
-	__rt_mutex_basic_init(lock);
-	rt_mutex_set_owner(lock, proxy_owner);
+		if (timeout && !timeout->task) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (build_ww_mutex() && ww_ctx) {
+			ret = __ww_mutex_check_kill(rtm, waiter, ww_ctx);
+			if (ret)
+				break;
+		}
+
+		if (waiter == rt_mutex_top_waiter(lock))
+			owner = rt_mutex_owner(lock);
+		else
+			owner = NULL;
+		raw_spin_unlock_irq(&lock->wait_lock);
+
+		if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner))
+			schedule();
+
+		raw_spin_lock_irq(&lock->wait_lock);
+		set_current_state(state);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	return ret;
 }
 
-/**
- * rt_mutex_proxy_unlock - release a lock on behalf of owner
- *
- * @lock:	the rt_mutex to be locked
- *
- * No locking. Caller has to do serializing itself
- *
- * Special API call for PI-futex support. This merrily cleans up the rtmutex
- * (debugging) state. Concurrent operations on this rt_mutex are not
- * possible because it belongs to the pi_state which is about to be freed
- * and it is not longer visible to other tasks.
- */
-void __sched rt_mutex_proxy_unlock(struct rt_mutex *lock)
+static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
+					     struct rt_mutex_waiter *w)
 {
-	debug_rt_mutex_proxy_unlock(lock);
-	rt_mutex_set_owner(lock, NULL);
+	/*
+	 * If the result is not -EDEADLOCK or the caller requested
+	 * deadlock detection, nothing to do here.
+	 */
+	if (res != -EDEADLOCK || detect_deadlock)
+		return;
+
+	if (build_ww_mutex() && w->ww_ctx)
+		return;
+
+	/*
+	 * Yell loudly and stop the task right here.
+	 */
+	WARN(1, "rtmutex deadlock detected\n");
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+	}
 }
 
 /**
- * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
- * @lock:		the rt_mutex to take
- * @waiter:		the pre-initialized rt_mutex_waiter
- * @task:		the task to prepare
- *
- * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
- * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
- *
- * NOTE: does _NOT_ remove the @waiter on failure; must either call
- * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this.
- *
- * Returns:
- *  0 - task blocked on lock
- *  1 - acquired the lock for task, caller should wake it up
- * <0 - error
- *
- * Special API call for PI-futex support.
+ * __rt_mutex_slowlock - Locking slowpath invoked with lock::wait_lock held
+ * @lock:	The rtmutex to block lock
+ * @ww_ctx:	WW mutex context pointer
+ * @state:	The task state for sleeping
+ * @chwalk:	Indicator whether full or partial chainwalk is requested
+ * @waiter:	Initializer waiter for blocking
  */
-int __sched __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-					struct rt_mutex_waiter *waiter,
-					struct task_struct *task)
+static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
+				       struct ww_acquire_ctx *ww_ctx,
+				       unsigned int state,
+				       enum rtmutex_chainwalk chwalk,
+				       struct rt_mutex_waiter *waiter)
 {
+	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
+	struct ww_mutex *ww = ww_container_of(rtm);
 	int ret;
 
 	lockdep_assert_held(&lock->wait_lock);
 
-	if (try_to_take_rt_mutex(lock, task, NULL))
-		return 1;
+	/* Try to acquire the lock again: */
+	if (try_to_take_rt_mutex(lock, current, NULL)) {
+		if (build_ww_mutex() && ww_ctx) {
+			__ww_mutex_check_waiters(rtm, ww_ctx);
+			ww_mutex_lock_acquired(ww, ww_ctx);
+		}
+		return 0;
+	}
 
-	/* We enforce deadlock detection for futexes */
-	ret = task_blocks_on_rt_mutex(lock, waiter, task,
-				      RT_MUTEX_FULL_CHAINWALK);
+	set_current_state(state);
 
-	if (ret && !rt_mutex_owner(lock)) {
-		/*
-		 * Reset the return value. We might have
-		 * returned with -EDEADLK and the owner
-		 * released the lock while we were walking the
-		 * pi chain.  Let the waiter sort it out.
-		 */
-		ret = 0;
+	ret = task_blocks_on_rt_mutex(lock, waiter, current, ww_ctx, chwalk);
+	if (likely(!ret))
+		ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter);
+
+	if (likely(!ret)) {
+		/* acquired the lock */
+		if (build_ww_mutex() && ww_ctx) {
+			if (!ww_ctx->is_wait_die)
+				__ww_mutex_check_waiters(rtm, ww_ctx);
+			ww_mutex_lock_acquired(ww, ww_ctx);
+		}
+	} else {
+		__set_current_state(TASK_RUNNING);
+		remove_waiter(lock, waiter);
+		rt_mutex_handle_deadlock(ret, chwalk, waiter);
 	}
 
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit
+	 * unconditionally. We might have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock);
 	return ret;
 }
 
-/**
- * rt_mutex_start_proxy_lock() - Start lock acquisition for another task
- * @lock:		the rt_mutex to take
- * @waiter:		the pre-initialized rt_mutex_waiter
- * @task:		the task to prepare
- *
- * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
- * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
- *
- * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter
- * on failure.
- *
- * Returns:
- *  0 - task blocked on lock
- *  1 - acquired the lock for task, caller should wake it up
- * <0 - error
- *
- * Special API call for PI-futex support.
- */
-int __sched rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-				      struct rt_mutex_waiter *waiter,
-				      struct task_struct *task)
+static inline int __rt_mutex_slowlock_locked(struct rt_mutex_base *lock,
+					     struct ww_acquire_ctx *ww_ctx,
+					     unsigned int state)
 {
+	struct rt_mutex_waiter waiter;
 	int ret;
 
-	raw_spin_lock_irq(&lock->wait_lock);
-	ret = __rt_mutex_start_proxy_lock(lock, waiter, task);
-	if (unlikely(ret))
-		remove_waiter(lock, waiter);
-	raw_spin_unlock_irq(&lock->wait_lock);
+	rt_mutex_init_waiter(&waiter);
+	waiter.ww_ctx = ww_ctx;
 
+	ret = __rt_mutex_slowlock(lock, ww_ctx, state, RT_MUTEX_MIN_CHAINWALK,
+				  &waiter);
+
+	debug_rt_mutex_free_waiter(&waiter);
 	return ret;
 }
 
-/**
- * rt_mutex_wait_proxy_lock() - Wait for lock acquisition
- * @lock:		the rt_mutex we were woken on
- * @to:			the timeout, null if none. hrtimer should already have
- *			been started.
- * @waiter:		the pre-initialized rt_mutex_waiter
- *
- * Wait for the lock acquisition started on our behalf by
- * rt_mutex_start_proxy_lock(). Upon failure, the caller must call
- * rt_mutex_cleanup_proxy_lock().
- *
- * Returns:
- *  0 - success
- * <0 - error, one of -EINTR, -ETIMEDOUT
- *
- * Special API call for PI-futex support
+/*
+ * rt_mutex_slowlock - Locking slowpath invoked when fast path fails
+ * @lock:	The rtmutex to block lock
+ * @ww_ctx:	WW mutex context pointer
+ * @state:	The task state for sleeping
  */
-int __sched rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
-				     struct hrtimer_sleeper *to,
-				     struct rt_mutex_waiter *waiter)
+static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
+				     struct ww_acquire_ctx *ww_ctx,
+				     unsigned int state)
 {
+	unsigned long flags;
 	int ret;
 
-	raw_spin_lock_irq(&lock->wait_lock);
-	/* sleep on the mutex */
-	set_current_state(TASK_INTERRUPTIBLE);
-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
 	/*
-	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
-	 * have to fix that up.
+	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
+	 * be called in early boot if the cmpxchg() fast path is disabled
+	 * (debug, no architecture support). In this case we will acquire the
+	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
+	 * enable interrupts in that early boot case. So we need to use the
+	 * irqsave/restore variants.
 	 */
-	fixup_rt_mutex_waiters(lock);
-	raw_spin_unlock_irq(&lock->wait_lock);
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	ret = __rt_mutex_slowlock_locked(lock, ww_ctx, state);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return ret;
 }
 
+static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
+					   unsigned int state)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return 0;
+
+	return rt_mutex_slowlock(lock, NULL, state);
+}
+#endif /* RT_MUTEX_BUILD_MUTEX */
+
+#ifdef RT_MUTEX_BUILD_SPINLOCKS
+/*
+ * Functions required for spin/rw_lock substitution on RT kernels
+ */
+
 /**
- * rt_mutex_cleanup_proxy_lock() - Cleanup failed lock acquisition
- * @lock:		the rt_mutex we were woken on
- * @waiter:		the pre-initialized rt_mutex_waiter
- *
- * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or
- * rt_mutex_wait_proxy_lock().
- *
- * Unless we acquired the lock; we're still enqueued on the wait-list and can
- * in fact still be granted ownership until we're removed. Therefore we can
- * find we are in fact the owner and must disregard the
- * rt_mutex_wait_proxy_lock() failure.
- *
- * Returns:
- *  true  - did the cleanup, we done.
- *  false - we acquired the lock after rt_mutex_wait_proxy_lock() returned,
- *          caller should disregards its return value.
- *
- * Special API call for PI-futex support
+ * rtlock_slowlock_locked - Slow path lock acquisition for RT locks
+ * @lock:	The underlying RT mutex
  */
-bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
-					 struct rt_mutex_waiter *waiter)
+static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock)
 {
-	bool cleanup = false;
+	struct rt_mutex_waiter waiter;
+	struct task_struct *owner;
 
-	raw_spin_lock_irq(&lock->wait_lock);
-	/*
-	 * Do an unconditional try-lock, this deals with the lock stealing
-	 * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter()
-	 * sets a NULL owner.
-	 *
-	 * We're not interested in the return value, because the subsequent
-	 * test on rt_mutex_owner() will infer that. If the trylock succeeded,
-	 * we will own the lock and it will have removed the waiter. If we
-	 * failed the trylock, we're still not owner and we need to remove
-	 * ourselves.
-	 */
-	try_to_take_rt_mutex(lock, current, waiter);
-	/*
-	 * Unless we're the owner; we're still enqueued on the wait_list.
-	 * So check if we became owner, if not, take us off the wait_list.
-	 */
-	if (rt_mutex_owner(lock) != current) {
-		remove_waiter(lock, waiter);
-		cleanup = true;
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (try_to_take_rt_mutex(lock, current, NULL))
+		return;
+
+	rt_mutex_init_rtlock_waiter(&waiter);
+
+	/* Save current state and set state to TASK_RTLOCK_WAIT */
+	current_save_and_set_rtlock_wait_state();
+
+	task_blocks_on_rt_mutex(lock, &waiter, current, NULL, RT_MUTEX_MIN_CHAINWALK);
+
+	for (;;) {
+		/* Try to acquire the lock again */
+		if (try_to_take_rt_mutex(lock, current, &waiter))
+			break;
+
+		if (&waiter == rt_mutex_top_waiter(lock))
+			owner = rt_mutex_owner(lock);
+		else
+			owner = NULL;
+		raw_spin_unlock_irq(&lock->wait_lock);
+
+		if (!owner || !rtmutex_spin_on_owner(lock, &waiter, owner))
+			schedule_rtlock();
+
+		raw_spin_lock_irq(&lock->wait_lock);
+		set_current_state(TASK_RTLOCK_WAIT);
 	}
+
+	/* Restore the task state */
+	current_restore_rtlock_saved_state();
+
 	/*
-	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
-	 * have to fix that up.
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally.
+	 * We might have to fix that up:
 	 */
 	fixup_rt_mutex_waiters(lock);
-
-	raw_spin_unlock_irq(&lock->wait_lock);
-
-	return cleanup;
+	debug_rt_mutex_free_waiter(&waiter);
 }
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-void rt_mutex_debug_task_free(struct task_struct *task)
+static __always_inline void __sched rtlock_slowlock(struct rt_mutex_base *lock)
 {
-	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
-	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	rtlock_slowlock_locked(lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 }
-#endif
+
+#endif /* RT_MUTEX_BUILD_SPINLOCKS */
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
new file mode 100644
index 000000000000..5c9299aaabae
--- /dev/null
+++ b/kernel/locking/rtmutex_api.c
@@ -0,0 +1,590 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rtmutex API
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_MUTEX
+#include "rtmutex.c"
+
+/*
+ * Max number of times we'll walk the boosting chain:
+ */
+int max_lock_depth = 1024;
+
+/*
+ * Debug aware fast / slowpath lock,trylock,unlock
+ *
+ * The atomic acquire/release ops are compiled away, when either the
+ * architecture does not support cmpxchg or when debugging is enabled.
+ */
+static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
+						  unsigned int state,
+						  unsigned int subclass)
+{
+	int ret;
+
+	might_sleep();
+	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	ret = __rt_mutex_lock(&lock->rtmutex, state);
+	if (ret)
+		mutex_release(&lock->dep_map, _RET_IP_);
+	return ret;
+}
+
+void rt_mutex_base_init(struct rt_mutex_base *rtb)
+{
+	__rt_mutex_base_init(rtb);
+}
+EXPORT_SYMBOL(rt_mutex_base_init);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/**
+ * rt_mutex_lock_nested - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ * @subclass: the lockdep subclass
+ */
+void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
+
+#else /* !CONFIG_DEBUG_LOCK_ALLOC */
+
+/**
+ * rt_mutex_lock - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ */
+void __sched rt_mutex_lock(struct rt_mutex *lock)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock);
+#endif
+
+/**
+ * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
+ *
+ * @lock:		the rt_mutex to be locked
+ *
+ * Returns:
+ *  0		on success
+ * -EINTR	when interrupted by a signal
+ */
+int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
+{
+	return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
+
+/**
+ * rt_mutex_trylock - try to lock a rt_mutex
+ *
+ * @lock:	the rt_mutex to be locked
+ *
+ * This function can only be called in thread context. It's safe to call it
+ * from atomic regions, but not from hard or soft interrupt context.
+ *
+ * Returns:
+ *  1 on success
+ *  0 on contention
+ */
+int __sched rt_mutex_trylock(struct rt_mutex *lock)
+{
+	int ret;
+
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
+		return 0;
+
+	ret = __rt_mutex_trylock(&lock->rtmutex);
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_mutex_trylock);
+
+/**
+ * rt_mutex_unlock - unlock a rt_mutex
+ *
+ * @lock: the rt_mutex to be unlocked
+ */
+void __sched rt_mutex_unlock(struct rt_mutex *lock)
+{
+	mutex_release(&lock->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&lock->rtmutex);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_unlock);
+
+/*
+ * Futex variants, must not use fastpath.
+ */
+int __sched rt_mutex_futex_trylock(struct rt_mutex_base *lock)
+{
+	return rt_mutex_slowtrylock(lock);
+}
+
+int __sched __rt_mutex_futex_trylock(struct rt_mutex_base *lock)
+{
+	return __rt_mutex_slowtrylock(lock);
+}
+
+/**
+ * __rt_mutex_futex_unlock - Futex variant, that since futex variants
+ * do not use the fast-path, can be simple and will not need to retry.
+ *
+ * @lock:	The rt_mutex to be unlocked
+ * @wqh:	The wake queue head from which to get the next lock waiter
+ */
+bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
+				     struct rt_wake_q_head *wqh)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	debug_rt_mutex_unlock(lock);
+
+	if (!rt_mutex_has_waiters(lock)) {
+		lock->owner = NULL;
+		return false; /* done */
+	}
+
+	/*
+	 * We've already deboosted, mark_wakeup_next_waiter() will
+	 * retain preempt_disabled when we drop the wait_lock, to
+	 * avoid inversion prior to the wakeup.  preempt_disable()
+	 * therein pairs with rt_mutex_postunlock().
+	 */
+	mark_wakeup_next_waiter(wqh, lock);
+
+	return true; /* call postunlock() */
+}
+
+void __sched rt_mutex_futex_unlock(struct rt_mutex_base *lock)
+{
+	DEFINE_RT_WAKE_Q(wqh);
+	unsigned long flags;
+	bool postunlock;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	postunlock = __rt_mutex_futex_unlock(lock, &wqh);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	if (postunlock)
+		rt_mutex_postunlock(&wqh);
+}
+
+/**
+ * __rt_mutex_init - initialize the rt_mutex
+ *
+ * @lock:	The rt_mutex to be initialized
+ * @name:	The lock name used for debugging
+ * @key:	The lock class key used for debugging
+ *
+ * Initialize the rt_mutex to unlocked state.
+ *
+ * Initializing of a locked rt_mutex is not allowed
+ */
+void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name,
+			     struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	__rt_mutex_base_init(&lock->rtmutex);
+	lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL_GPL(__rt_mutex_init);
+
+/**
+ * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
+ *				proxy owner
+ *
+ * @lock:	the rt_mutex to be locked
+ * @proxy_owner:the task to set as owner
+ *
+ * No locking. Caller has to do serializing itself
+ *
+ * Special API call for PI-futex support. This initializes the rtmutex and
+ * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not
+ * possible at this point because the pi_state which contains the rtmutex
+ * is not yet visible to other tasks.
+ */
+void __sched rt_mutex_init_proxy_locked(struct rt_mutex_base *lock,
+					struct task_struct *proxy_owner)
+{
+	static struct lock_class_key pi_futex_key;
+
+	__rt_mutex_base_init(lock);
+	/*
+	 * On PREEMPT_RT the futex hashbucket spinlock becomes 'sleeping'
+	 * and rtmutex based. That causes a lockdep false positive, because
+	 * some of the futex functions invoke spin_unlock(&hb->lock) with
+	 * the wait_lock of the rtmutex associated to the pi_futex held.
+	 * spin_unlock() in turn takes wait_lock of the rtmutex on which
+	 * the spinlock is based, which makes lockdep notice a lock
+	 * recursion. Give the futex/rtmutex wait_lock a separate key.
+	 */
+	lockdep_set_class(&lock->wait_lock, &pi_futex_key);
+	rt_mutex_set_owner(lock, proxy_owner);
+}
+
+/**
+ * rt_mutex_proxy_unlock - release a lock on behalf of owner
+ *
+ * @lock:	the rt_mutex to be locked
+ *
+ * No locking. Caller has to do serializing itself
+ *
+ * Special API call for PI-futex support. This just cleans up the rtmutex
+ * (debugging) state. Concurrent operations on this rt_mutex are not
+ * possible because it belongs to the pi_state which is about to be freed
+ * and it is not longer visible to other tasks.
+ */
+void __sched rt_mutex_proxy_unlock(struct rt_mutex_base *lock)
+{
+	debug_rt_mutex_proxy_unlock(lock);
+	rt_mutex_set_owner(lock, NULL);
+}
+
+/**
+ * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock:		the rt_mutex to take
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ * @task:		the task to prepare
+ *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: does _NOT_ remove the @waiter on failure; must either call
+ * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this.
+ *
+ * Returns:
+ *  0 - task blocked on lock
+ *  1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for PI-futex support.
+ */
+int __sched __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+					struct rt_mutex_waiter *waiter,
+					struct task_struct *task)
+{
+	int ret;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (try_to_take_rt_mutex(lock, task, NULL))
+		return 1;
+
+	/* We enforce deadlock detection for futexes */
+	ret = task_blocks_on_rt_mutex(lock, waiter, task, NULL,
+				      RT_MUTEX_FULL_CHAINWALK);
+
+	if (ret && !rt_mutex_owner(lock)) {
+		/*
+		 * Reset the return value. We might have
+		 * returned with -EDEADLK and the owner
+		 * released the lock while we were walking the
+		 * pi chain.  Let the waiter sort it out.
+		 */
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/**
+ * rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock:		the rt_mutex to take
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ * @task:		the task to prepare
+ *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter
+ * on failure.
+ *
+ * Returns:
+ *  0 - task blocked on lock
+ *  1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for PI-futex support.
+ */
+int __sched rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				      struct rt_mutex_waiter *waiter,
+				      struct task_struct *task)
+{
+	int ret;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	ret = __rt_mutex_start_proxy_lock(lock, waiter, task);
+	if (unlikely(ret))
+		remove_waiter(lock, waiter);
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return ret;
+}
+
+/**
+ * rt_mutex_wait_proxy_lock() - Wait for lock acquisition
+ * @lock:		the rt_mutex we were woken on
+ * @to:			the timeout, null if none. hrtimer should already have
+ *			been started.
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ *
+ * Wait for the lock acquisition started on our behalf by
+ * rt_mutex_start_proxy_lock(). Upon failure, the caller must call
+ * rt_mutex_cleanup_proxy_lock().
+ *
+ * Returns:
+ *  0 - success
+ * <0 - error, one of -EINTR, -ETIMEDOUT
+ *
+ * Special API call for PI-futex support
+ */
+int __sched rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock,
+				     struct hrtimer_sleeper *to,
+				     struct rt_mutex_waiter *waiter)
+{
+	int ret;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	/* sleep on the mutex */
+	set_current_state(TASK_INTERRUPTIBLE);
+	ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter);
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+	 * have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock);
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return ret;
+}
+
+/**
+ * rt_mutex_cleanup_proxy_lock() - Cleanup failed lock acquisition
+ * @lock:		the rt_mutex we were woken on
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ *
+ * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or
+ * rt_mutex_wait_proxy_lock().
+ *
+ * Unless we acquired the lock; we're still enqueued on the wait-list and can
+ * in fact still be granted ownership until we're removed. Therefore we can
+ * find we are in fact the owner and must disregard the
+ * rt_mutex_wait_proxy_lock() failure.
+ *
+ * Returns:
+ *  true  - did the cleanup, we done.
+ *  false - we acquired the lock after rt_mutex_wait_proxy_lock() returned,
+ *          caller should disregards its return value.
+ *
+ * Special API call for PI-futex support
+ */
+bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock,
+					 struct rt_mutex_waiter *waiter)
+{
+	bool cleanup = false;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	/*
+	 * Do an unconditional try-lock, this deals with the lock stealing
+	 * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter()
+	 * sets a NULL owner.
+	 *
+	 * We're not interested in the return value, because the subsequent
+	 * test on rt_mutex_owner() will infer that. If the trylock succeeded,
+	 * we will own the lock and it will have removed the waiter. If we
+	 * failed the trylock, we're still not owner and we need to remove
+	 * ourselves.
+	 */
+	try_to_take_rt_mutex(lock, current, waiter);
+	/*
+	 * Unless we're the owner; we're still enqueued on the wait_list.
+	 * So check if we became owner, if not, take us off the wait_list.
+	 */
+	if (rt_mutex_owner(lock) != current) {
+		remove_waiter(lock, waiter);
+		cleanup = true;
+	}
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+	 * have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock);
+
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return cleanup;
+}
+
+/*
+ * Recheck the pi chain, in case we got a priority setting
+ *
+ * Called from sched_setscheduler
+ */
+void __sched rt_mutex_adjust_pi(struct task_struct *task)
+{
+	struct rt_mutex_waiter *waiter;
+	struct rt_mutex_base *next_lock;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+	waiter = task->pi_blocked_on;
+	if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		return;
+	}
+	next_lock = waiter->lock;
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+	get_task_struct(task);
+
+	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
+				   next_lock, NULL, task);
+}
+
+/*
+ * Performs the wakeup of the top-waiter and re-enables preemption.
+ */
+void __sched rt_mutex_postunlock(struct rt_wake_q_head *wqh)
+{
+	rt_mutex_wake_up_q(wqh);
+}
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
+	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+/* Mutexes */
+void __mutex_rt_init(struct mutex *mutex, const char *name,
+		     struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
+	lockdep_init_map_wait(&mutex->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL(__mutex_rt_init);
+
+static __always_inline int __mutex_lock_common(struct mutex *lock,
+					       unsigned int state,
+					       unsigned int subclass,
+					       struct lockdep_map *nest_lock,
+					       unsigned long ip)
+{
+	int ret;
+
+	might_sleep();
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+	ret = __rt_mutex_lock(&lock->rtmutex, state);
+	if (ret)
+		mutex_release(&lock->dep_map, ip);
+	else
+		lock_acquired(&lock->dep_map, ip);
+	return ret;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+
+void __sched _mutex_lock_nest_lock(struct mutex *lock,
+				   struct lockdep_map *nest_lock)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, nest_lock, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
+int __sched mutex_lock_interruptible_nested(struct mutex *lock,
+					    unsigned int subclass)
+{
+	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+
+int __sched mutex_lock_killable_nested(struct mutex *lock,
+					    unsigned int subclass)
+{
+	return __mutex_lock_common(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+void __sched mutex_lock_io_nested(struct mutex *lock, unsigned int subclass)
+{
+	int token;
+
+	might_sleep();
+
+	token = io_schedule_prepare();
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io_nested);
+
+#else /* CONFIG_DEBUG_LOCK_ALLOC */
+
+void __sched mutex_lock(struct mutex *lock)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock);
+
+int __sched mutex_lock_interruptible(struct mutex *lock)
+{
+	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock_interruptible);
+
+int __sched mutex_lock_killable(struct mutex *lock)
+{
+	return __mutex_lock_common(lock, TASK_KILLABLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
+void __sched mutex_lock_io(struct mutex *lock)
+{
+	int token = io_schedule_prepare();
+
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL(mutex_lock_io);
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+
+int __sched mutex_trylock(struct mutex *lock)
+{
+	int ret;
+
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
+		return 0;
+
+	ret = __rt_mutex_trylock(&lock->rtmutex);
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL(mutex_trylock);
+
+void __sched mutex_unlock(struct mutex *lock)
+{
+	mutex_release(&lock->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&lock->rtmutex);
+}
+EXPORT_SYMBOL(mutex_unlock);
+
+#endif /* CONFIG_PREEMPT_RT */
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index a90c22abdbca..c47e8361bfb5 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -25,29 +25,90 @@
  * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree
  * @task:		task reference to the blocked task
  * @lock:		Pointer to the rt_mutex on which the waiter blocks
+ * @wake_state:		Wakeup state to use (TASK_NORMAL or TASK_RTLOCK_WAIT)
  * @prio:		Priority of the waiter
  * @deadline:		Deadline of the waiter if applicable
+ * @ww_ctx:		WW context pointer
  */
 struct rt_mutex_waiter {
 	struct rb_node		tree_entry;
 	struct rb_node		pi_tree_entry;
 	struct task_struct	*task;
-	struct rt_mutex		*lock;
+	struct rt_mutex_base	*lock;
+	unsigned int		wake_state;
 	int			prio;
 	u64			deadline;
+	struct ww_acquire_ctx	*ww_ctx;
 };
 
+/**
+ * rt_wake_q_head - Wrapper around regular wake_q_head to support
+ *		    "sleeping" spinlocks on RT
+ * @head:		The regular wake_q_head for sleeping lock variants
+ * @rtlock_task:	Task pointer for RT lock (spin/rwlock) wakeups
+ */
+struct rt_wake_q_head {
+	struct wake_q_head	head;
+	struct task_struct	*rtlock_task;
+};
+
+#define DEFINE_RT_WAKE_Q(name)						\
+	struct rt_wake_q_head name = {					\
+		.head		= WAKE_Q_HEAD_INITIALIZER(name.head),	\
+		.rtlock_task	= NULL,					\
+	}
+
+/*
+ * PI-futex support (proxy locking functions, etc.):
+ */
+extern void rt_mutex_init_proxy_locked(struct rt_mutex_base *lock,
+				       struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex_base *lock);
+extern int __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock,
+			       struct hrtimer_sleeper *to,
+			       struct rt_mutex_waiter *waiter);
+extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock,
+				 struct rt_mutex_waiter *waiter);
+
+extern int rt_mutex_futex_trylock(struct rt_mutex_base *l);
+extern int __rt_mutex_futex_trylock(struct rt_mutex_base *l);
+
+extern void rt_mutex_futex_unlock(struct rt_mutex_base *lock);
+extern bool __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
+				struct rt_wake_q_head *wqh);
+
+extern void rt_mutex_postunlock(struct rt_wake_q_head *wqh);
+
 /*
  * Must be guarded because this header is included from rcu/tree_plugin.h
  * unconditionally.
  */
 #ifdef CONFIG_RT_MUTEXES
-static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
+static inline int rt_mutex_has_waiters(struct rt_mutex_base *lock)
 {
 	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);
 }
 
-static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock)
+/*
+ * Lockless speculative check whether @waiter is still the top waiter on
+ * @lock. This is solely comparing pointers and not derefencing the
+ * leftmost entry which might be about to vanish.
+ */
+static inline bool rt_mutex_waiter_is_top_waiter(struct rt_mutex_base *lock,
+						 struct rt_mutex_waiter *waiter)
+{
+	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
+
+	return rb_entry(leftmost, struct rt_mutex_waiter, tree_entry) == waiter;
+}
+
+static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex_base *lock)
 {
 	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
 	struct rt_mutex_waiter *w = NULL;
@@ -72,19 +133,12 @@ static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
 
 #define RT_MUTEX_HAS_WAITERS	1UL
 
-static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
 {
 	unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
 
 	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
 }
-#else /* CONFIG_RT_MUTEXES */
-/* Used in rcu/tree_plugin.h */
-static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
-{
-	return NULL;
-}
-#endif  /* !CONFIG_RT_MUTEXES */
 
 /*
  * Constants for rt mutex functions which have a selectable deadlock
@@ -101,49 +155,21 @@ enum rtmutex_chainwalk {
 	RT_MUTEX_FULL_CHAINWALK,
 };
 
-static inline void __rt_mutex_basic_init(struct rt_mutex *lock)
+static inline void __rt_mutex_base_init(struct rt_mutex_base *lock)
 {
-	lock->owner = NULL;
 	raw_spin_lock_init(&lock->wait_lock);
 	lock->waiters = RB_ROOT_CACHED;
+	lock->owner = NULL;
 }
 
-/*
- * PI-futex support (proxy locking functions, etc.):
- */
-extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
-				       struct task_struct *proxy_owner);
-extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
-extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-				     struct rt_mutex_waiter *waiter,
-				     struct task_struct *task);
-extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-				     struct rt_mutex_waiter *waiter,
-				     struct task_struct *task);
-extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
-			       struct hrtimer_sleeper *to,
-			       struct rt_mutex_waiter *waiter);
-extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
-				 struct rt_mutex_waiter *waiter);
-
-extern int rt_mutex_futex_trylock(struct rt_mutex *l);
-extern int __rt_mutex_futex_trylock(struct rt_mutex *l);
-
-extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
-extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				 struct wake_q_head *wqh);
-
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
-
 /* Debug functions */
-static inline void debug_rt_mutex_unlock(struct rt_mutex *lock)
+static inline void debug_rt_mutex_unlock(struct rt_mutex_base *lock)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
 		DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
 }
 
-static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex_base *lock)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
 		DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
@@ -161,4 +187,27 @@ static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 		memset(waiter, 0x22, sizeof(*waiter));
 }
 
+static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	debug_rt_mutex_init_waiter(waiter);
+	RB_CLEAR_NODE(&waiter->pi_tree_entry);
+	RB_CLEAR_NODE(&waiter->tree_entry);
+	waiter->wake_state = TASK_NORMAL;
+	waiter->task = NULL;
+}
+
+static inline void rt_mutex_init_rtlock_waiter(struct rt_mutex_waiter *waiter)
+{
+	rt_mutex_init_waiter(waiter);
+	waiter->wake_state = TASK_RTLOCK_WAIT;
+}
+
+#else /* CONFIG_RT_MUTEXES */
+/* Used in rcu/tree_plugin.h */
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
+{
+	return NULL;
+}
+#endif  /* !CONFIG_RT_MUTEXES */
+
 #endif
diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c
new file mode 100644
index 000000000000..4ba15088e640
--- /dev/null
+++ b/kernel/locking/rwbase_rt.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * RT-specific reader/writer semaphores and reader/writer locks
+ *
+ * down_write/write_lock()
+ *  1) Lock rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical section
+ *  4) Mark it write locked
+ *
+ * up_write/write_unlock()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS, so readers can use the fast path again
+ *  3) Unlock rtmutex, to release blocked readers
+ *
+ * down_read/read_lock()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take tmutex::wait_lock, which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on tmutex
+ *  5) unlock rtmutex, goto 1)
+ *
+ * up_read/read_unlock()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in down_write()/write_lock() #3
+ *
+ * down_read/read_lock()#3 has the consequence, that rw semaphores and rw
+ * locks on RT are not writer fair, but writers, which should be avoided in
+ * RT tasks (think mmap_sem), are subject to the rtmutex priority/DL
+ * inheritance mechanism.
+ *
+ * It's possible to make the rw primitives writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers
+ * to block on the rtmutex, but the rtmutex would have to be proxy locked
+ * for one reader after the other. We can't use multi-reader inheritance
+ * because there is no way to support that with SCHED_DEADLINE.
+ * Implementing the one by one reader boosting/handover mechanism is a
+ * major surgery for a very dubious value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ *
+ * Common code shared between RT rw_semaphore and rwlock
+ */
+
+static __always_inline int rwbase_read_trylock(struct rwbase_rt *rwb)
+{
+	int r;
+
+	/*
+	 * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&rwb->readers); r < 0;) {
+		if (likely(atomic_try_cmpxchg(&rwb->readers, &r, r + 1)))
+			return 1;
+	}
+	return 0;
+}
+
+static int __sched __rwbase_read_lock(struct rwbase_rt *rwb,
+				      unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	int ret;
+
+	raw_spin_lock_irq(&rtm->wait_lock);
+	/*
+	 * Allow readers, as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&rwb->readers) != WRITER_BIAS) {
+		atomic_inc(&rwb->readers);
+		raw_spin_unlock_irq(&rtm->wait_lock);
+		return 0;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					wait()
+	 * down_read()
+	 * unlock(m->wait_lock)
+	 *			up_read()
+	 *			wake(Writer)
+	 *					lock(m->wait_lock)
+	 *					sem->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					up_write()
+	 *					sem->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					wait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call up_read(), which might be unbound.
+	 */
+
+	/*
+	 * For rwlocks this returns 0 unconditionally, so the below
+	 * !ret conditionals are optimized out.
+	 */
+	ret = rwbase_rtmutex_slowlock_locked(rtm, state);
+
+	/*
+	 * On success the rtmutex is held, so there can't be a writer
+	 * active. Increment the reader count and immediately drop the
+	 * rtmutex again.
+	 *
+	 * rtmutex->wait_lock has to be unlocked in any case of course.
+	 */
+	if (!ret)
+		atomic_inc(&rwb->readers);
+	raw_spin_unlock_irq(&rtm->wait_lock);
+	if (!ret)
+		rwbase_rtmutex_unlock(rtm);
+	return ret;
+}
+
+static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb,
+					    unsigned int state)
+{
+	if (rwbase_read_trylock(rwb))
+		return 0;
+
+	return __rwbase_read_lock(rwb, state);
+}
+
+static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb,
+					 unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	struct task_struct *owner;
+
+	raw_spin_lock_irq(&rtm->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path (due to a signal), but to
+	 * clean up rwb->readers it needs to acquire rtm->wait_lock. The
+	 * worst case which can happen is a spurious wakeup.
+	 */
+	owner = rt_mutex_owner(rtm);
+	if (owner)
+		wake_up_state(owner, state);
+
+	raw_spin_unlock_irq(&rtm->wait_lock);
+}
+
+static __always_inline void rwbase_read_unlock(struct rwbase_rt *rwb,
+					       unsigned int state)
+{
+	/*
+	 * rwb->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical section.
+	 */
+	if (unlikely(atomic_dec_and_test(&rwb->readers)))
+		__rwbase_read_unlock(rwb, state);
+}
+
+static inline void __rwbase_write_unlock(struct rwbase_rt *rwb, int bias,
+					 unsigned long flags)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+
+	atomic_add(READER_BIAS - bias, &rwb->readers);
+	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+	rwbase_rtmutex_unlock(rtm);
+}
+
+static inline void rwbase_write_unlock(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	__rwbase_write_unlock(rwb, WRITER_BIAS, flags);
+}
+
+static inline void rwbase_write_downgrade(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	/* Release it and account current as reader */
+	__rwbase_write_unlock(rwb, WRITER_BIAS - 1, flags);
+}
+
+static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
+				     unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	if (rwbase_rtmutex_lock_state(rtm, state))
+		return -EINTR;
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &rwb->readers);
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	/*
+	 * set_current_state() for rw_semaphore
+	 * current_save_and_set_rtlock_wait_state() for rwlock
+	 */
+	rwbase_set_and_save_current_state(state);
+
+	/* Block until all readers have left the critical section. */
+	for (; atomic_read(&rwb->readers);) {
+		/* Optimized out for rwlocks */
+		if (rwbase_signal_pending_state(state, current)) {
+			__set_current_state(TASK_RUNNING);
+			__rwbase_write_unlock(rwb, 0, flags);
+			return -EINTR;
+		}
+		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+
+		/*
+		 * Schedule and wait for the readers to leave the critical
+		 * section. The last reader leaving it wakes the waiter.
+		 */
+		if (atomic_read(&rwb->readers) != 0)
+			rwbase_schedule();
+		set_current_state(state);
+		raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	}
+
+	atomic_set(&rwb->readers, WRITER_BIAS);
+	rwbase_restore_current_state();
+	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+	return 0;
+}
+
+static inline int rwbase_write_trylock(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	if (!rwbase_rtmutex_trylock(rtm))
+		return 0;
+
+	atomic_sub(READER_BIAS, &rwb->readers);
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	if (!atomic_read(&rwb->readers)) {
+		atomic_set(&rwb->readers, WRITER_BIAS);
+		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+		return 1;
+	}
+	__rwbase_write_unlock(rwb, 0, flags);
+	return 0;
+}
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 16bfbb10c74d..9215b4d6a9de 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -28,6 +28,7 @@
 #include <linux/rwsem.h>
 #include <linux/atomic.h>
 
+#ifndef CONFIG_PREEMPT_RT
 #include "lock_events.h"
 
 /*
@@ -1165,7 +1166,7 @@ out_nolock:
  * handle waking up a waiter on the semaphore
  * - up_read/up_write has decremented the active part of count if we come here
  */
-static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem, long count)
+static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 {
 	unsigned long flags;
 	DEFINE_WAKE_Q(wake_q);
@@ -1297,7 +1298,7 @@ static inline void __up_read(struct rw_semaphore *sem)
 	if (unlikely((tmp & (RWSEM_LOCK_MASK|RWSEM_FLAG_WAITERS)) ==
 		      RWSEM_FLAG_WAITERS)) {
 		clear_nonspinnable(sem);
-		rwsem_wake(sem, tmp);
+		rwsem_wake(sem);
 	}
 }
 
@@ -1319,7 +1320,7 @@ static inline void __up_write(struct rw_semaphore *sem)
 	rwsem_clear_owner(sem);
 	tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count);
 	if (unlikely(tmp & RWSEM_FLAG_WAITERS))
-		rwsem_wake(sem, tmp);
+		rwsem_wake(sem);
 }
 
 /*
@@ -1344,6 +1345,114 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
 		rwsem_downgrade_wake(sem);
 }
 
+#else /* !CONFIG_PREEMPT_RT */
+
+#define RT_MUTEX_BUILD_MUTEX
+#include "rtmutex.c"
+
+#define rwbase_set_and_save_current_state(state)	\
+	set_current_state(state)
+
+#define rwbase_restore_current_state()			\
+	__set_current_state(TASK_RUNNING)
+
+#define rwbase_rtmutex_lock_state(rtm, state)		\
+	__rt_mutex_lock(rtm, state)
+
+#define rwbase_rtmutex_slowlock_locked(rtm, state)	\
+	__rt_mutex_slowlock_locked(rtm, NULL, state)
+
+#define rwbase_rtmutex_unlock(rtm)			\
+	__rt_mutex_unlock(rtm)
+
+#define rwbase_rtmutex_trylock(rtm)			\
+	__rt_mutex_trylock(rtm)
+
+#define rwbase_signal_pending_state(state, current)	\
+	signal_pending_state(state, current)
+
+#define rwbase_schedule()				\
+	schedule()
+
+#include "rwbase_rt.c"
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __rwsem_init(struct rw_semaphore *sem, const char *name,
+		  struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map_wait(&sem->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL(__rwsem_init);
+#endif
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+	rwbase_read_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __down_read_interruptible(struct rw_semaphore *sem)
+{
+	return rwbase_read_lock(&sem->rwbase, TASK_INTERRUPTIBLE);
+}
+
+static inline int __down_read_killable(struct rw_semaphore *sem)
+{
+	return rwbase_read_lock(&sem->rwbase, TASK_KILLABLE);
+}
+
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+	return rwbase_read_trylock(&sem->rwbase);
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+	rwbase_read_unlock(&sem->rwbase, TASK_NORMAL);
+}
+
+static inline void __sched __down_write(struct rw_semaphore *sem)
+{
+	rwbase_write_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __sched __down_write_killable(struct rw_semaphore *sem)
+{
+	return rwbase_write_lock(&sem->rwbase, TASK_KILLABLE);
+}
+
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+	return rwbase_write_trylock(&sem->rwbase);
+}
+
+static inline void __up_write(struct rw_semaphore *sem)
+{
+	rwbase_write_unlock(&sem->rwbase);
+}
+
+static inline void __downgrade_write(struct rw_semaphore *sem)
+{
+	rwbase_write_downgrade(&sem->rwbase);
+}
+
+/* Debug stubs for the common API */
+#define DEBUG_RWSEMS_WARN_ON(c, sem)
+
+static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
+					    struct task_struct *owner)
+{
+}
+
+static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+{
+	int count = atomic_read(&sem->rwbase.readers);
+
+	return count < 0 && count != READER_BIAS;
+}
+
+#endif /* CONFIG_PREEMPT_RT */
+
 /*
  * lock for reading
  */
diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c
index 9aa855a96c4a..9ee381e4d2a4 100644
--- a/kernel/locking/semaphore.c
+++ b/kernel/locking/semaphore.c
@@ -54,6 +54,7 @@ void down(struct semaphore *sem)
 {
 	unsigned long flags;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;
@@ -77,6 +78,7 @@ int down_interruptible(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;
@@ -103,6 +105,7 @@ int down_killable(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;
@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;
diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
index c8d7ad9fb9b2..c5830cfa379a 100644
--- a/kernel/locking/spinlock.c
+++ b/kernel/locking/spinlock.c
@@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)		\
  *         __[spin|read|write]_lock_bh()
  */
 BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT
 BUILD_LOCK_OPS(read, rwlock);
 BUILD_LOCK_OPS(write, rwlock);
+#endif
 
 #endif
 
@@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
 EXPORT_SYMBOL(_raw_spin_unlock_bh);
 #endif
 
+#ifndef CONFIG_PREEMPT_RT
+
 #ifndef CONFIG_INLINE_READ_TRYLOCK
 int __lockfunc _raw_read_trylock(rwlock_t *lock)
 {
@@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
 EXPORT_SYMBOL(_raw_write_unlock_bh);
 #endif
 
+#endif /* !CONFIG_PREEMPT_RT */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index b9d93087ee66..14235671a1a7 100644
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
 
 EXPORT_SYMBOL(__raw_spin_lock_init);
 
+#ifndef CONFIG_PREEMPT_RT
 void __rwlock_init(rwlock_t *lock, const char *name,
 		   struct lock_class_key *key)
 {
@@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const char *name,
 }
 
 EXPORT_SYMBOL(__rwlock_init);
+#endif
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
@@ -139,6 +141,7 @@ void do_raw_spin_unlock(raw_spinlock_t *lock)
 	arch_spin_unlock(&lock->raw_lock);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 static void rwlock_bug(rwlock_t *lock, const char *msg)
 {
 	if (!debug_locks_off())
@@ -228,3 +231,5 @@ void do_raw_write_unlock(rwlock_t *lock)
 	debug_write_unlock(lock);
 	arch_write_unlock(&lock->raw_lock);
 }
+
+#endif /* !CONFIG_PREEMPT_RT */
diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c
new file mode 100644
index 000000000000..d2912e44d61f
--- /dev/null
+++ b/kernel/locking/spinlock_rt.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PREEMPT_RT substitution for spin/rw_locks
+ *
+ * spinlocks and rwlocks on RT are based on rtmutexes, with a few twists to
+ * resemble the non RT semantics:
+ *
+ * - Contrary to plain rtmutexes, spinlocks and rwlocks are state
+ *   preserving. The task state is saved before blocking on the underlying
+ *   rtmutex, and restored when the lock has been acquired. Regular wakeups
+ *   during that time are redirected to the saved state so no wake up is
+ *   missed.
+ *
+ * - Non RT spin/rwlocks disable preemption and eventually interrupts.
+ *   Disabling preemption has the side effect of disabling migration and
+ *   preventing RCU grace periods.
+ *
+ *   The RT substitutions explicitly disable migration and take
+ *   rcu_read_lock() across the lock held section.
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_SPINLOCKS
+#include "rtmutex.c"
+
+static __always_inline void rtlock_lock(struct rt_mutex_base *rtm)
+{
+	if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		rtlock_slowlock(rtm);
+}
+
+static __always_inline void __rt_spin_lock(spinlock_t *lock)
+{
+	___might_sleep(__FILE__, __LINE__, 0);
+	rtlock_lock(&lock->lock);
+	rcu_read_lock();
+	migrate_disable();
+}
+
+void __sched rt_spin_lock(spinlock_t *lock)
+{
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_nested);
+
+void __sched rt_spin_lock_nest_lock(spinlock_t *lock,
+				    struct lockdep_map *nest_lock)
+{
+	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_nest_lock);
+#endif
+
+void __sched rt_spin_unlock(spinlock_t *lock)
+{
+	spin_release(&lock->dep_map, _RET_IP_);
+	migrate_enable();
+	rcu_read_unlock();
+
+	if (unlikely(!rt_mutex_cmpxchg_release(&lock->lock, current, NULL)))
+		rt_mutex_slowunlock(&lock->lock);
+}
+EXPORT_SYMBOL(rt_spin_unlock);
+
+/*
+ * Wait for the lock to get unlocked: instead of polling for an unlock
+ * (like raw spinlocks do), lock and unlock, to force the kernel to
+ * schedule if there's contention:
+ */
+void __sched rt_spin_lock_unlock(spinlock_t *lock)
+{
+	spin_lock(lock);
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_unlock);
+
+static __always_inline int __rt_spin_trylock(spinlock_t *lock)
+{
+	int ret = 1;
+
+	if (unlikely(!rt_mutex_cmpxchg_acquire(&lock->lock, NULL, current)))
+		ret = rt_mutex_slowtrylock(&lock->lock);
+
+	if (ret) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+
+int __sched rt_spin_trylock(spinlock_t *lock)
+{
+	return __rt_spin_trylock(lock);
+}
+EXPORT_SYMBOL(rt_spin_trylock);
+
+int __sched rt_spin_trylock_bh(spinlock_t *lock)
+{
+	int ret;
+
+	local_bh_disable();
+	ret = __rt_spin_trylock(lock);
+	if (!ret)
+		local_bh_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_bh);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __rt_spin_lock_init(spinlock_t *lock, const char *name,
+			 struct lock_class_key *key, bool percpu)
+{
+	u8 type = percpu ? LD_LOCK_PERCPU : LD_LOCK_NORMAL;
+
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map_type(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG,
+			      LD_WAIT_INV, type);
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+#endif
+
+/*
+ * RT-specific reader/writer locks
+ */
+#define rwbase_set_and_save_current_state(state)	\
+	current_save_and_set_rtlock_wait_state()
+
+#define rwbase_restore_current_state()			\
+	current_restore_rtlock_saved_state()
+
+static __always_inline int
+rwbase_rtmutex_lock_state(struct rt_mutex_base *rtm, unsigned int state)
+{
+	if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		rtlock_slowlock(rtm);
+	return 0;
+}
+
+static __always_inline int
+rwbase_rtmutex_slowlock_locked(struct rt_mutex_base *rtm, unsigned int state)
+{
+	rtlock_slowlock_locked(rtm);
+	return 0;
+}
+
+static __always_inline void rwbase_rtmutex_unlock(struct rt_mutex_base *rtm)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(rtm, current, NULL)))
+		return;
+
+	rt_mutex_slowunlock(rtm);
+}
+
+static __always_inline int  rwbase_rtmutex_trylock(struct rt_mutex_base *rtm)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		return 1;
+
+	return rt_mutex_slowtrylock(rtm);
+}
+
+#define rwbase_signal_pending_state(state, current)	(0)
+
+#define rwbase_schedule()				\
+	schedule_rtlock()
+
+#include "rwbase_rt.c"
+/*
+ * The common functions which get wrapped into the rwlock API.
+ */
+int __sched rt_read_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	ret = rwbase_read_trylock(&rwlock->rwbase);
+	if (ret) {
+		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+int __sched rt_write_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	ret = rwbase_write_trylock(&rwlock->rwbase);
+	if (ret) {
+		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+void __sched rt_read_lock(rwlock_t *rwlock)
+{
+	___might_sleep(__FILE__, __LINE__, 0);
+	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+	rwbase_read_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+	rcu_read_lock();
+	migrate_disable();
+}
+EXPORT_SYMBOL(rt_read_lock);
+
+void __sched rt_write_lock(rwlock_t *rwlock)
+{
+	___might_sleep(__FILE__, __LINE__, 0);
+	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+	rwbase_write_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+	rcu_read_lock();
+	migrate_disable();
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+void __sched rt_read_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	migrate_enable();
+	rcu_read_unlock();
+	rwbase_read_unlock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+void __sched rt_write_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	rcu_read_unlock();
+	migrate_enable();
+	rwbase_write_unlock(&rwlock->rwbase);
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+int __sched rt_rwlock_is_contended(rwlock_t *rwlock)
+{
+	return rw_base_is_contended(&rwlock->rwbase);
+}
+EXPORT_SYMBOL(rt_rwlock_is_contended);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __rt_rwlock_init(rwlock_t *rwlock, const char *name,
+		      struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock));
+	lockdep_init_map_wait(&rwlock->dep_map, name, key, 0, LD_WAIT_CONFIG);
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
+#endif
diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h
new file mode 100644
index 000000000000..56f139201f24
--- /dev/null
+++ b/kernel/locking/ww_mutex.h
@@ -0,0 +1,569 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef WW_RT
+
+#define MUTEX		mutex
+#define MUTEX_WAITER	mutex_waiter
+
+static inline struct mutex_waiter *
+__ww_waiter_first(struct mutex *lock)
+{
+	struct mutex_waiter *w;
+
+	w = list_first_entry(&lock->wait_list, struct mutex_waiter, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_next(struct mutex *lock, struct mutex_waiter *w)
+{
+	w = list_next_entry(w, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_prev(struct mutex *lock, struct mutex_waiter *w)
+{
+	w = list_prev_entry(w, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_last(struct mutex *lock)
+{
+	struct mutex_waiter *w;
+
+	w = list_last_entry(&lock->wait_list, struct mutex_waiter, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline void
+__ww_waiter_add(struct mutex *lock, struct mutex_waiter *waiter, struct mutex_waiter *pos)
+{
+	struct list_head *p = &lock->wait_list;
+	if (pos)
+		p = &pos->list;
+	__mutex_add_waiter(lock, waiter, p);
+}
+
+static inline struct task_struct *
+__ww_mutex_owner(struct mutex *lock)
+{
+	return __mutex_owner(lock);
+}
+
+static inline bool
+__ww_mutex_has_waiters(struct mutex *lock)
+{
+	return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS;
+}
+
+static inline void lock_wait_lock(struct mutex *lock)
+{
+	raw_spin_lock(&lock->wait_lock);
+}
+
+static inline void unlock_wait_lock(struct mutex *lock)
+{
+	raw_spin_unlock(&lock->wait_lock);
+}
+
+static inline void lockdep_assert_wait_lock_held(struct mutex *lock)
+{
+	lockdep_assert_held(&lock->wait_lock);
+}
+
+#else /* WW_RT */
+
+#define MUTEX		rt_mutex
+#define MUTEX_WAITER	rt_mutex_waiter
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_first(struct rt_mutex *lock)
+{
+	struct rb_node *n = rb_first(&lock->rtmutex.waiters.rb_root);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree_entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_next(struct rt_mutex *lock, struct rt_mutex_waiter *w)
+{
+	struct rb_node *n = rb_next(&w->tree_entry);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree_entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_prev(struct rt_mutex *lock, struct rt_mutex_waiter *w)
+{
+	struct rb_node *n = rb_prev(&w->tree_entry);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree_entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_last(struct rt_mutex *lock)
+{
+	struct rb_node *n = rb_last(&lock->rtmutex.waiters.rb_root);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree_entry);
+}
+
+static inline void
+__ww_waiter_add(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, struct rt_mutex_waiter *pos)
+{
+	/* RT unconditionally adds the waiter first and then removes it on error */
+}
+
+static inline struct task_struct *
+__ww_mutex_owner(struct rt_mutex *lock)
+{
+	return rt_mutex_owner(&lock->rtmutex);
+}
+
+static inline bool
+__ww_mutex_has_waiters(struct rt_mutex *lock)
+{
+	return rt_mutex_has_waiters(&lock->rtmutex);
+}
+
+static inline void lock_wait_lock(struct rt_mutex *lock)
+{
+	raw_spin_lock(&lock->rtmutex.wait_lock);
+}
+
+static inline void unlock_wait_lock(struct rt_mutex *lock)
+{
+	raw_spin_unlock(&lock->rtmutex.wait_lock);
+}
+
+static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock)
+{
+	lockdep_assert_held(&lock->rtmutex.wait_lock);
+}
+
+#endif /* WW_RT */
+
+/*
+ * Wait-Die:
+ *   The newer transactions are killed when:
+ *     It (the new transaction) makes a request for a lock being held
+ *     by an older transaction.
+ *
+ * Wound-Wait:
+ *   The newer transactions are wounded when:
+ *     An older transaction makes a request for a lock being held by
+ *     the newer transaction.
+ */
+
+/*
+ * Associate the ww_mutex @ww with the context @ww_ctx under which we acquired
+ * it.
+ */
+static __always_inline void
+ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx)
+{
+#ifdef DEBUG_WW_MUTEXES
+	/*
+	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+	 * but released with a normal mutex_unlock in this call.
+	 *
+	 * This should never happen, always use ww_mutex_unlock.
+	 */
+	DEBUG_LOCKS_WARN_ON(ww->ctx);
+
+	/*
+	 * Not quite done after calling ww_acquire_done() ?
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+	if (ww_ctx->contending_lock) {
+		/*
+		 * After -EDEADLK you tried to
+		 * acquire a different ww_mutex? Bad!
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+		/*
+		 * You called ww_mutex_lock after receiving -EDEADLK,
+		 * but 'forgot' to unlock everything else first?
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+		ww_ctx->contending_lock = NULL;
+	}
+
+	/*
+	 * Naughty, using a different class will lead to undefined behavior!
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+	ww_ctx->acquired++;
+	ww->ctx = ww_ctx;
+}
+
+/*
+ * Determine if @a is 'less' than @b. IOW, either @a is a lower priority task
+ * or, when of equal priority, a younger transaction than @b.
+ *
+ * Depending on the algorithm, @a will either need to wait for @b, or die.
+ */
+static inline bool
+__ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b)
+{
+/*
+ * Can only do the RT prio for WW_RT, because task->prio isn't stable due to PI,
+ * so the wait_list ordering will go wobbly. rt_mutex re-queues the waiter and
+ * isn't affected by this.
+ */
+#ifdef WW_RT
+	/* kernel prio; less is more */
+	int a_prio = a->task->prio;
+	int b_prio = b->task->prio;
+
+	if (rt_prio(a_prio) || rt_prio(b_prio)) {
+
+		if (a_prio > b_prio)
+			return true;
+
+		if (a_prio < b_prio)
+			return false;
+
+		/* equal static prio */
+
+		if (dl_prio(a_prio)) {
+			if (dl_time_before(b->task->dl.deadline,
+					   a->task->dl.deadline))
+				return true;
+
+			if (dl_time_before(a->task->dl.deadline,
+					   b->task->dl.deadline))
+				return false;
+		}
+
+		/* equal prio */
+	}
+#endif
+
+	/* FIFO order tie break -- bigger is younger */
+	return (signed long)(a->stamp - b->stamp) > 0;
+}
+
+/*
+ * Wait-Die; wake a lesser waiter context (when locks held) such that it can
+ * die.
+ *
+ * Among waiters with context, only the first one can have other locks acquired
+ * already (ctx->acquired > 0), because __ww_mutex_add_waiter() and
+ * __ww_mutex_check_kill() wake any but the earliest context.
+ */
+static bool
+__ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter,
+	       struct ww_acquire_ctx *ww_ctx)
+{
+	if (!ww_ctx->is_wait_die)
+		return false;
+
+	if (waiter->ww_ctx->acquired > 0 && __ww_ctx_less(waiter->ww_ctx, ww_ctx)) {
+#ifndef WW_RT
+		debug_mutex_wake_waiter(lock, waiter);
+#endif
+		wake_up_process(waiter->task);
+	}
+
+	return true;
+}
+
+/*
+ * Wound-Wait; wound a lesser @hold_ctx if it holds the lock.
+ *
+ * Wound the lock holder if there are waiters with more important transactions
+ * than the lock holders. Even if multiple waiters may wound the lock holder,
+ * it's sufficient that only one does.
+ */
+static bool __ww_mutex_wound(struct MUTEX *lock,
+			     struct ww_acquire_ctx *ww_ctx,
+			     struct ww_acquire_ctx *hold_ctx)
+{
+	struct task_struct *owner = __ww_mutex_owner(lock);
+
+	lockdep_assert_wait_lock_held(lock);
+
+	/*
+	 * Possible through __ww_mutex_add_waiter() when we race with
+	 * ww_mutex_set_context_fastpath(). In that case we'll get here again
+	 * through __ww_mutex_check_waiters().
+	 */
+	if (!hold_ctx)
+		return false;
+
+	/*
+	 * Can have !owner because of __mutex_unlock_slowpath(), but if owner,
+	 * it cannot go away because we'll have FLAG_WAITERS set and hold
+	 * wait_lock.
+	 */
+	if (!owner)
+		return false;
+
+	if (ww_ctx->acquired > 0 && __ww_ctx_less(hold_ctx, ww_ctx)) {
+		hold_ctx->wounded = 1;
+
+		/*
+		 * wake_up_process() paired with set_current_state()
+		 * inserts sufficient barriers to make sure @owner either sees
+		 * it's wounded in __ww_mutex_check_kill() or has a
+		 * wakeup pending to re-read the wounded state.
+		 */
+		if (owner != current)
+			wake_up_process(owner);
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * We just acquired @lock under @ww_ctx, if there are more important contexts
+ * waiting behind us on the wait-list, check if they need to die, or wound us.
+ *
+ * See __ww_mutex_add_waiter() for the list-order construction; basically the
+ * list is ordered by stamp, smallest (oldest) first.
+ *
+ * This relies on never mixing wait-die/wound-wait on the same wait-list;
+ * which is currently ensured by that being a ww_class property.
+ *
+ * The current task must not be on the wait list.
+ */
+static void
+__ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx)
+{
+	struct MUTEX_WAITER *cur;
+
+	lockdep_assert_wait_lock_held(lock);
+
+	for (cur = __ww_waiter_first(lock); cur;
+	     cur = __ww_waiter_next(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		if (__ww_mutex_die(lock, cur, ww_ctx) ||
+		    __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx))
+			break;
+	}
+}
+
+/*
+ * After acquiring lock with fastpath, where we do not hold wait_lock, set ctx
+ * and wake up any waiters so they can recheck.
+ */
+static __always_inline void
+ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	ww_mutex_lock_acquired(lock, ctx);
+
+	/*
+	 * The lock->ctx update should be visible on all cores before
+	 * the WAITERS check is done, otherwise contended waiters might be
+	 * missed. The contended waiters will either see ww_ctx == NULL
+	 * and keep spinning, or it will acquire wait_lock, add itself
+	 * to waiter list and sleep.
+	 */
+	smp_mb(); /* See comments above and below. */
+
+	/*
+	 * [W] ww->ctx = ctx	    [W] MUTEX_FLAG_WAITERS
+	 *     MB		        MB
+	 * [R] MUTEX_FLAG_WAITERS   [R] ww->ctx
+	 *
+	 * The memory barrier above pairs with the memory barrier in
+	 * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx
+	 * and/or !empty list.
+	 */
+	if (likely(!__ww_mutex_has_waiters(&lock->base)))
+		return;
+
+	/*
+	 * Uh oh, we raced in fastpath, check if any of the waiters need to
+	 * die or wound us.
+	 */
+	lock_wait_lock(&lock->base);
+	__ww_mutex_check_waiters(&lock->base, ctx);
+	unlock_wait_lock(&lock->base);
+}
+
+static __always_inline int
+__ww_mutex_kill(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx)
+{
+	if (ww_ctx->acquired > 0) {
+#ifdef DEBUG_WW_MUTEXES
+		struct ww_mutex *ww;
+
+		ww = container_of(lock, struct ww_mutex, base);
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock);
+		ww_ctx->contending_lock = ww;
+#endif
+		return -EDEADLK;
+	}
+
+	return 0;
+}
+
+/*
+ * Check the wound condition for the current lock acquire.
+ *
+ * Wound-Wait: If we're wounded, kill ourself.
+ *
+ * Wait-Die: If we're trying to acquire a lock already held by an older
+ *           context, kill ourselves.
+ *
+ * Since __ww_mutex_add_waiter() orders the wait-list on stamp, we only have to
+ * look at waiters before us in the wait-list.
+ */
+static inline int
+__ww_mutex_check_kill(struct MUTEX *lock, struct MUTEX_WAITER *waiter,
+		      struct ww_acquire_ctx *ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
+	struct MUTEX_WAITER *cur;
+
+	if (ctx->acquired == 0)
+		return 0;
+
+	if (!ctx->is_wait_die) {
+		if (ctx->wounded)
+			return __ww_mutex_kill(lock, ctx);
+
+		return 0;
+	}
+
+	if (hold_ctx && __ww_ctx_less(ctx, hold_ctx))
+		return __ww_mutex_kill(lock, ctx);
+
+	/*
+	 * If there is a waiter in front of us that has a context, then its
+	 * stamp is earlier than ours and we must kill ourself.
+	 */
+	for (cur = __ww_waiter_prev(lock, waiter); cur;
+	     cur = __ww_waiter_prev(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		return __ww_mutex_kill(lock, ctx);
+	}
+
+	return 0;
+}
+
+/*
+ * Add @waiter to the wait-list, keep the wait-list ordered by stamp, smallest
+ * first. Such that older contexts are preferred to acquire the lock over
+ * younger contexts.
+ *
+ * Waiters without context are interspersed in FIFO order.
+ *
+ * Furthermore, for Wait-Die kill ourself immediately when possible (there are
+ * older contexts already waiting) to avoid unnecessary waiting and for
+ * Wound-Wait ensure we wound the owning context when it is younger.
+ */
+static inline int
+__ww_mutex_add_waiter(struct MUTEX_WAITER *waiter,
+		      struct MUTEX *lock,
+		      struct ww_acquire_ctx *ww_ctx)
+{
+	struct MUTEX_WAITER *cur, *pos = NULL;
+	bool is_wait_die;
+
+	if (!ww_ctx) {
+		__ww_waiter_add(lock, waiter, NULL);
+		return 0;
+	}
+
+	is_wait_die = ww_ctx->is_wait_die;
+
+	/*
+	 * Add the waiter before the first waiter with a higher stamp.
+	 * Waiters without a context are skipped to avoid starving
+	 * them. Wait-Die waiters may die here. Wound-Wait waiters
+	 * never die here, but they are sorted in stamp order and
+	 * may wound the lock holder.
+	 */
+	for (cur = __ww_waiter_last(lock); cur;
+	     cur = __ww_waiter_prev(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		if (__ww_ctx_less(ww_ctx, cur->ww_ctx)) {
+			/*
+			 * Wait-Die: if we find an older context waiting, there
+			 * is no point in queueing behind it, as we'd have to
+			 * die the moment it would acquire the lock.
+			 */
+			if (is_wait_die) {
+				int ret = __ww_mutex_kill(lock, ww_ctx);
+
+				if (ret)
+					return ret;
+			}
+
+			break;
+		}
+
+		pos = cur;
+
+		/* Wait-Die: ensure younger waiters die. */
+		__ww_mutex_die(lock, cur, ww_ctx);
+	}
+
+	__ww_waiter_add(lock, waiter, pos);
+
+	/*
+	 * Wound-Wait: if we're blocking on a mutex owned by a younger context,
+	 * wound that such that we might proceed.
+	 */
+	if (!is_wait_die) {
+		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+
+		/*
+		 * See ww_mutex_set_context_fastpath(). Orders setting
+		 * MUTEX_FLAG_WAITERS vs the ww->ctx load,
+		 * such that either we or the fastpath will wound @ww->ctx.
+		 */
+		smp_mb();
+		__ww_mutex_wound(lock, ww_ctx, ww->ctx);
+	}
+
+	return 0;
+}
+
+static inline void __ww_mutex_unlock(struct ww_mutex *lock)
+{
+	if (lock->ctx) {
+#ifdef DEBUG_WW_MUTEXES
+		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+		if (lock->ctx->acquired > 0)
+			lock->ctx->acquired--;
+		lock->ctx = NULL;
+	}
+}
diff --git a/kernel/locking/ww_rt_mutex.c b/kernel/locking/ww_rt_mutex.c
new file mode 100644
index 000000000000..3f1fff7d2780
--- /dev/null
+++ b/kernel/locking/ww_rt_mutex.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rtmutex API
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_MUTEX
+#define WW_RT
+#include "rtmutex.c"
+
+static int __sched
+__ww_rt_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx,
+		   unsigned int state, unsigned long ip)
+{
+	struct lockdep_map __maybe_unused *nest_lock = NULL;
+	struct rt_mutex *rtm = &lock->base;
+	int ret;
+
+	might_sleep();
+
+	if (ww_ctx) {
+		if (unlikely(ww_ctx == READ_ONCE(lock->ctx)))
+			return -EALREADY;
+
+		/*
+		 * Reset the wounded flag after a kill. No other process can
+		 * race and wound us here, since they can't have a valid owner
+		 * pointer if we don't have any locks held.
+		 */
+		if (ww_ctx->acquired == 0)
+			ww_ctx->wounded = 0;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+		nest_lock = &ww_ctx->dep_map;
+#endif
+	}
+	mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip);
+
+	if (likely(rt_mutex_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) {
+		if (ww_ctx)
+			ww_mutex_set_context_fastpath(lock, ww_ctx);
+		return 0;
+	}
+
+	ret = rt_mutex_slowlock(&rtm->rtmutex, ww_ctx, state);
+
+	if (ret)
+		mutex_release(&rtm->dep_map, ip);
+	return ret;
+}
+
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	return __ww_rt_mutex_lock(lock, ctx, TASK_UNINTERRUPTIBLE, _RET_IP_);
+}
+EXPORT_SYMBOL(ww_mutex_lock);
+
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	return __ww_rt_mutex_lock(lock, ctx, TASK_INTERRUPTIBLE, _RET_IP_);
+}
+EXPORT_SYMBOL(ww_mutex_lock_interruptible);
+
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+	struct rt_mutex *rtm = &lock->base;
+
+	__ww_mutex_unlock(lock);
+
+	mutex_release(&rtm->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&rtm->rtmutex);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);