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authorIngo Molnar <mingo@kernel.org>2019-09-16 14:04:28 +0200
committerIngo Molnar <mingo@kernel.org>2019-09-16 14:05:04 +0200
commit563c4f85f9f0d63b712081d5b4522152cdcb8b6b (patch)
tree92351ab2d60d5fd7ce5745d21c9a60ce6d46c5dd /kernel/locking
parent4adcdcea717cb2d8436bef00dd689aa5bc76f11b (diff)
parent09c7e8b21d67c3c78ab9701dbc0fb1e9f14a0ba5 (diff)
downloadlinux-563c4f85f9f0d63b712081d5b4522152cdcb8b6b.tar.bz2
Merge branch 'sched/rt' into sched/core, to pick up -rt changes
Pick up the first couple of patches working towards PREEMPT_RT. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c13
-rw-r--r--kernel/locking/lockdep_proc.c3
-rw-r--r--kernel/locking/mutex.c11
-rw-r--r--kernel/locking/rwsem.c28
4 files changed, 40 insertions, 15 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 341f52117f88..4861cf8e274b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -448,7 +448,7 @@ static void print_lockdep_off(const char *bug_msg)
unsigned long nr_stack_trace_entries;
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the graph_lock.
@@ -491,7 +491,7 @@ unsigned int max_lockdep_depth;
DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
#endif
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
/*
* Locking printouts:
*/
@@ -2969,7 +2969,7 @@ static void check_chain_key(struct task_struct *curr)
#endif
}
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_PROVE_LOCKING
static int mark_lock(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit);
@@ -3608,7 +3608,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
return ret;
}
-#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+#else /* CONFIG_PROVE_LOCKING */
static inline int
mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
@@ -3627,7 +3627,7 @@ static inline int separate_irq_context(struct task_struct *curr,
return 0;
}
-#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+#endif /* CONFIG_PROVE_LOCKING */
/*
* Initialize a lock instance's lock-class mapping info:
@@ -4321,8 +4321,7 @@ static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie
*/
static void check_flags(unsigned long flags)
{
-#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
- defined(CONFIG_TRACE_IRQFLAGS)
+#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP)
if (!debug_locks)
return;
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 65b6a1600c8f..bda006f8a88b 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -200,7 +200,6 @@ static void lockdep_stats_debug_show(struct seq_file *m)
static int lockdep_stats_show(struct seq_file *m, void *v)
{
- struct lock_class *class;
unsigned long nr_unused = 0, nr_uncategorized = 0,
nr_irq_safe = 0, nr_irq_unsafe = 0,
nr_softirq_safe = 0, nr_softirq_unsafe = 0,
@@ -211,6 +210,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
sum_forward_deps = 0;
#ifdef CONFIG_PROVE_LOCKING
+ struct lock_class *class;
+
list_for_each_entry(class, &all_lock_classes, lock_entry) {
if (class->usage_mask == 0)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index edd1c082dbf5..5e069734363c 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -908,6 +908,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
might_sleep();
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+#endif
+
ww = container_of(lock, struct ww_mutex, base);
if (use_ww_ctx && ww_ctx) {
if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
@@ -1379,8 +1383,13 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
*/
int __sched mutex_trylock(struct mutex *lock)
{
- bool locked = __mutex_trylock(lock);
+ bool locked;
+
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+#endif
+ locked = __mutex_trylock(lock);
if (locked)
mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 37524a47f002..bd0f0d05724c 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -666,7 +666,11 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem,
preempt_disable();
rcu_read_lock();
owner = rwsem_owner_flags(sem, &flags);
- if ((flags & nonspinnable) || (owner && !owner_on_cpu(owner)))
+ /*
+ * Don't check the read-owner as the entry may be stale.
+ */
+ if ((flags & nonspinnable) ||
+ (owner && !(flags & RWSEM_READER_OWNED) && !owner_on_cpu(owner)))
ret = false;
rcu_read_unlock();
preempt_enable();
@@ -1000,6 +1004,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, int state)
atomic_long_add(-RWSEM_READER_BIAS, &sem->count);
adjustment = 0;
if (rwsem_optimistic_spin(sem, false)) {
+ /* rwsem_optimistic_spin() implies ACQUIRE on success */
/*
* Wake up other readers in the wait list if the front
* waiter is a reader.
@@ -1014,6 +1019,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, int state)
}
return sem;
} else if (rwsem_reader_phase_trylock(sem, waiter.last_rowner)) {
+ /* rwsem_reader_phase_trylock() implies ACQUIRE on success */
return sem;
}
@@ -1032,6 +1038,8 @@ queue:
*/
if (adjustment && !(atomic_long_read(&sem->count) &
(RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) {
+ /* Provide lock ACQUIRE */
+ smp_acquire__after_ctrl_dep();
raw_spin_unlock_irq(&sem->wait_lock);
rwsem_set_reader_owned(sem);
lockevent_inc(rwsem_rlock_fast);
@@ -1065,15 +1073,18 @@ queue:
wake_up_q(&wake_q);
/* wait to be given the lock */
- while (true) {
+ for (;;) {
set_current_state(state);
- if (!waiter.task)
+ if (!smp_load_acquire(&waiter.task)) {
+ /* Matches rwsem_mark_wake()'s smp_store_release(). */
break;
+ }
if (signal_pending_state(state, current)) {
raw_spin_lock_irq(&sem->wait_lock);
if (waiter.task)
goto out_nolock;
raw_spin_unlock_irq(&sem->wait_lock);
+ /* Ordered by sem->wait_lock against rwsem_mark_wake(). */
break;
}
schedule();
@@ -1083,6 +1094,7 @@ queue:
__set_current_state(TASK_RUNNING);
lockevent_inc(rwsem_rlock);
return sem;
+
out_nolock:
list_del(&waiter.list);
if (list_empty(&sem->wait_list)) {
@@ -1123,8 +1135,10 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state)
/* do optimistic spinning and steal lock if possible */
if (rwsem_can_spin_on_owner(sem, RWSEM_WR_NONSPINNABLE) &&
- rwsem_optimistic_spin(sem, true))
+ rwsem_optimistic_spin(sem, true)) {
+ /* rwsem_optimistic_spin() implies ACQUIRE on success */
return sem;
+ }
/*
* Disable reader optimistic spinning for this rwsem after
@@ -1184,9 +1198,11 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state)
wait:
/* wait until we successfully acquire the lock */
set_current_state(state);
- while (true) {
- if (rwsem_try_write_lock(sem, wstate))
+ for (;;) {
+ if (rwsem_try_write_lock(sem, wstate)) {
+ /* rwsem_try_write_lock() implies ACQUIRE on success */
break;
+ }
raw_spin_unlock_irq(&sem->wait_lock);