Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Ingo Molnar:
 "Misc fixes:

   - Fix a S390 boot hang that was caused by the lock-break logic.
     Remove lock-break to begin with, as review suggested it was
     unreasonably fragile and our confidence in its continued good
     health is lower than our confidence in its removal.

   - Remove the lockdep cross-release checking code for now, because of
     unresolved false positive warnings. This should make lockdep work
     well everywhere again.

   - Get rid of the final (and single) ACCESS_ONCE() straggler and
     remove the API from v4.15.

   - Fix a liblockdep build warning"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools/lib/lockdep: Add missing declaration of 'pr_cont()'
  checkpatch: Remove ACCESS_ONCE() warning
  compiler.h: Remove ACCESS_ONCE()
  tools/include: Remove ACCESS_ONCE()
  tools/perf: Convert ACCESS_ONCE() to READ_ONCE()
  locking/lockdep: Remove the cross-release locking checks
  locking/core: Remove break_lock field when CONFIG_GENERIC_LOCKBREAK=y
  locking/core: Fix deadlock during boot on systems with GENERIC_LOCKBREAK

2 files changed, 38 insertions, 627 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 670d8d7d8087..5fa1324a4f29 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -57,10 +57,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/lock.h>
 
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-#include <linux/slab.h>
-#endif
-
 #ifdef CONFIG_PROVE_LOCKING
 int prove_locking = 1;
 module_param(prove_locking, int, 0644);
@@ -75,19 +71,6 @@ module_param(lock_stat, int, 0644);
 #define lock_stat 0
 #endif
 
-#ifdef CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK
-static int crossrelease_fullstack = 1;
-#else
-static int crossrelease_fullstack;
-#endif
-static int __init allow_crossrelease_fullstack(char *str)
-{
-	crossrelease_fullstack = 1;
-	return 0;
-}
-
-early_param("crossrelease_fullstack", allow_crossrelease_fullstack);
-
 /*
  * lockdep_lock: protects the lockdep graph, the hashes and the
  *               class/list/hash allocators.
@@ -740,18 +723,6 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
 	return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL);
 }
 
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-static void cross_init(struct lockdep_map *lock, int cross);
-static int cross_lock(struct lockdep_map *lock);
-static int lock_acquire_crosslock(struct held_lock *hlock);
-static int lock_release_crosslock(struct lockdep_map *lock);
-#else
-static inline void cross_init(struct lockdep_map *lock, int cross) {}
-static inline int cross_lock(struct lockdep_map *lock) { return 0; }
-static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; }
-static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; }
-#endif
-
 /*
  * Register a lock's class in the hash-table, if the class is not present
  * yet. Otherwise we look it up. We cache the result in the lock object
@@ -1151,41 +1122,22 @@ print_circular_lock_scenario(struct held_lock *src,
 		printk(KERN_CONT "\n\n");
 	}
 
-	if (cross_lock(tgt->instance)) {
-		printk(" Possible unsafe locking scenario by crosslock:\n\n");
-		printk("       CPU0                    CPU1\n");
-		printk("       ----                    ----\n");
-		printk("  lock(");
-		__print_lock_name(parent);
-		printk(KERN_CONT ");\n");
-		printk("  lock(");
-		__print_lock_name(target);
-		printk(KERN_CONT ");\n");
-		printk("                               lock(");
-		__print_lock_name(source);
-		printk(KERN_CONT ");\n");
-		printk("                               unlock(");
-		__print_lock_name(target);
-		printk(KERN_CONT ");\n");
-		printk("\n *** DEADLOCK ***\n\n");
-	} else {
-		printk(" Possible unsafe locking scenario:\n\n");
-		printk("       CPU0                    CPU1\n");
-		printk("       ----                    ----\n");
-		printk("  lock(");
-		__print_lock_name(target);
-		printk(KERN_CONT ");\n");
-		printk("                               lock(");
-		__print_lock_name(parent);
-		printk(KERN_CONT ");\n");
-		printk("                               lock(");
-		__print_lock_name(target);
-		printk(KERN_CONT ");\n");
-		printk("  lock(");
-		__print_lock_name(source);
-		printk(KERN_CONT ");\n");
-		printk("\n *** DEADLOCK ***\n\n");
-	}
+	printk(" Possible unsafe locking scenario:\n\n");
+	printk("       CPU0                    CPU1\n");
+	printk("       ----                    ----\n");
+	printk("  lock(");
+	__print_lock_name(target);
+	printk(KERN_CONT ");\n");
+	printk("                               lock(");
+	__print_lock_name(parent);
+	printk(KERN_CONT ");\n");
+	printk("                               lock(");
+	__print_lock_name(target);
+	printk(KERN_CONT ");\n");
+	printk("  lock(");
+	__print_lock_name(source);
+	printk(KERN_CONT ");\n");
+	printk("\n *** DEADLOCK ***\n\n");
 }
 
 /*
@@ -1211,10 +1163,7 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth,
 		curr->comm, task_pid_nr(curr));
 	print_lock(check_src);
 
-	if (cross_lock(check_tgt->instance))
-		pr_warn("\nbut now in release context of a crosslock acquired at the following:\n");
-	else
-		pr_warn("\nbut task is already holding lock:\n");
+	pr_warn("\nbut task is already holding lock:\n");
 
 	print_lock(check_tgt);
 	pr_warn("\nwhich lock already depends on the new lock.\n\n");
@@ -1244,9 +1193,7 @@ static noinline int print_circular_bug(struct lock_list *this,
 	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
 		return 0;
 
-	if (cross_lock(check_tgt->instance))
-		this->trace = *trace;
-	else if (!save_trace(&this->trace))
+	if (!save_trace(&this->trace))
 		return 0;
 
 	depth = get_lock_depth(target);
@@ -1850,9 +1797,6 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
 		if (nest)
 			return 2;
 
-		if (cross_lock(prev->instance))
-			continue;
-
 		return print_deadlock_bug(curr, prev, next);
 	}
 	return 1;
@@ -2018,31 +1962,26 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
 	for (;;) {
 		int distance = curr->lockdep_depth - depth + 1;
 		hlock = curr->held_locks + depth - 1;
+
 		/*
-		 * Only non-crosslock entries get new dependencies added.
-		 * Crosslock entries will be added by commit later:
+		 * Only non-recursive-read entries get new dependencies
+		 * added:
 		 */
-		if (!cross_lock(hlock->instance)) {
+		if (hlock->read != 2 && hlock->check) {
+			int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace);
+			if (!ret)
+				return 0;
+
 			/*
-			 * Only non-recursive-read entries get new dependencies
-			 * added:
+			 * Stop after the first non-trylock entry,
+			 * as non-trylock entries have added their
+			 * own direct dependencies already, so this
+			 * lock is connected to them indirectly:
 			 */
-			if (hlock->read != 2 && hlock->check) {
-				int ret = check_prev_add(curr, hlock, next,
-							 distance, &trace, save_trace);
-				if (!ret)
-					return 0;
-
-				/*
-				 * Stop after the first non-trylock entry,
-				 * as non-trylock entries have added their
-				 * own direct dependencies already, so this
-				 * lock is connected to them indirectly:
-				 */
-				if (!hlock->trylock)
-					break;
-			}
+			if (!hlock->trylock)
+				break;
 		}
+
 		depth--;
 		/*
 		 * End of lock-stack?
@@ -3292,21 +3231,10 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
 void lockdep_init_map(struct lockdep_map *lock, const char *name,
 		      struct lock_class_key *key, int subclass)
 {
-	cross_init(lock, 0);
 	__lockdep_init_map(lock, name, key, subclass);
 }
 EXPORT_SYMBOL_GPL(lockdep_init_map);
 
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name,
-		      struct lock_class_key *key, int subclass)
-{
-	cross_init(lock, 1);
-	__lockdep_init_map(lock, name, key, subclass);
-}
-EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock);
-#endif
-
 struct lock_class_key __lockdep_no_validate__;
 EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
 
@@ -3362,7 +3290,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 	int chain_head = 0;
 	int class_idx;
 	u64 chain_key;
-	int ret;
 
 	if (unlikely(!debug_locks))
 		return 0;
@@ -3411,8 +3338,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 
 	class_idx = class - lock_classes + 1;
 
-	/* TODO: nest_lock is not implemented for crosslock yet. */
-	if (depth && !cross_lock(lock)) {
+	if (depth) {
 		hlock = curr->held_locks + depth - 1;
 		if (hlock->class_idx == class_idx && nest_lock) {
 			if (hlock->references) {
@@ -3500,14 +3426,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 	if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
 		return 0;
 
-	ret = lock_acquire_crosslock(hlock);
-	/*
-	 * 2 means normal acquire operations are needed. Otherwise, it's
-	 * ok just to return with '0:fail, 1:success'.
-	 */
-	if (ret != 2)
-		return ret;
-
 	curr->curr_chain_key = chain_key;
 	curr->lockdep_depth++;
 	check_chain_key(curr);
@@ -3745,19 +3663,11 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
 	struct task_struct *curr = current;
 	struct held_lock *hlock;
 	unsigned int depth;
-	int ret, i;
+	int i;
 
 	if (unlikely(!debug_locks))
 		return 0;
 
-	ret = lock_release_crosslock(lock);
-	/*
-	 * 2 means normal release operations are needed. Otherwise, it's
-	 * ok just to return with '0:fail, 1:success'.
-	 */
-	if (ret != 2)
-		return ret;
-
 	depth = curr->lockdep_depth;
 	/*
 	 * So we're all set to release this lock.. wait what lock? We don't
@@ -4675,495 +4585,3 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 	dump_stack();
 }
 EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
-
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-
-/*
- * Crossrelease works by recording a lock history for each thread and
- * connecting those historic locks that were taken after the
- * wait_for_completion() in the complete() context.
- *
- * Task-A				Task-B
- *
- *					mutex_lock(&A);
- *					mutex_unlock(&A);
- *
- * wait_for_completion(&C);
- *   lock_acquire_crosslock();
- *     atomic_inc_return(&cross_gen_id);
- *                                |
- *				  |	mutex_lock(&B);
- *				  |	mutex_unlock(&B);
- *                                |
- *				  |	complete(&C);
- *				  `--	  lock_commit_crosslock();
- *
- * Which will then add a dependency between B and C.
- */
-
-#define xhlock(i)         (current->xhlocks[(i) % MAX_XHLOCKS_NR])
-
-/*
- * Whenever a crosslock is held, cross_gen_id will be increased.
- */
-static atomic_t cross_gen_id; /* Can be wrapped */
-
-/*
- * Make an entry of the ring buffer invalid.
- */
-static inline void invalidate_xhlock(struct hist_lock *xhlock)
-{
-	/*
-	 * Normally, xhlock->hlock.instance must be !NULL.
-	 */
-	xhlock->hlock.instance = NULL;
-}
-
-/*
- * Lock history stacks; we have 2 nested lock history stacks:
- *
- *   HARD(IRQ)
- *   SOFT(IRQ)
- *
- * The thing is that once we complete a HARD/SOFT IRQ the future task locks
- * should not depend on any of the locks observed while running the IRQ.  So
- * what we do is rewind the history buffer and erase all our knowledge of that
- * temporal event.
- */
-
-void crossrelease_hist_start(enum xhlock_context_t c)
-{
-	struct task_struct *cur = current;
-
-	if (!cur->xhlocks)
-		return;
-
-	cur->xhlock_idx_hist[c] = cur->xhlock_idx;
-	cur->hist_id_save[c]    = cur->hist_id;
-}
-
-void crossrelease_hist_end(enum xhlock_context_t c)
-{
-	struct task_struct *cur = current;
-
-	if (cur->xhlocks) {
-		unsigned int idx = cur->xhlock_idx_hist[c];
-		struct hist_lock *h = &xhlock(idx);
-
-		cur->xhlock_idx = idx;
-
-		/* Check if the ring was overwritten. */
-		if (h->hist_id != cur->hist_id_save[c])
-			invalidate_xhlock(h);
-	}
-}
-
-/*
- * lockdep_invariant_state() is used to annotate independence inside a task, to
- * make one task look like multiple independent 'tasks'.
- *
- * Take for instance workqueues; each work is independent of the last. The
- * completion of a future work does not depend on the completion of a past work
- * (in general). Therefore we must not carry that (lock) dependency across
- * works.
- *
- * This is true for many things; pretty much all kthreads fall into this
- * pattern, where they have an invariant state and future completions do not
- * depend on past completions. Its just that since they all have the 'same'
- * form -- the kthread does the same over and over -- it doesn't typically
- * matter.
- *
- * The same is true for system-calls, once a system call is completed (we've
- * returned to userspace) the next system call does not depend on the lock
- * history of the previous system call.
- *
- * They key property for independence, this invariant state, is that it must be
- * a point where we hold no locks and have no history. Because if we were to
- * hold locks, the restore at _end() would not necessarily recover it's history
- * entry. Similarly, independence per-definition means it does not depend on
- * prior state.
- */
-void lockdep_invariant_state(bool force)
-{
-	/*
-	 * We call this at an invariant point, no current state, no history.
-	 * Verify the former, enforce the latter.
-	 */
-	WARN_ON_ONCE(!force && current->lockdep_depth);
-	if (current->xhlocks)
-		invalidate_xhlock(&xhlock(current->xhlock_idx));
-}
-
-static int cross_lock(struct lockdep_map *lock)
-{
-	return lock ? lock->cross : 0;
-}
-
-/*
- * This is needed to decide the relationship between wrapable variables.
- */
-static inline int before(unsigned int a, unsigned int b)
-{
-	return (int)(a - b) < 0;
-}
-
-static inline struct lock_class *xhlock_class(struct hist_lock *xhlock)
-{
-	return hlock_class(&xhlock->hlock);
-}
-
-static inline struct lock_class *xlock_class(struct cross_lock *xlock)
-{
-	return hlock_class(&xlock->hlock);
-}
-
-/*
- * Should we check a dependency with previous one?
- */
-static inline int depend_before(struct held_lock *hlock)
-{
-	return hlock->read != 2 && hlock->check && !hlock->trylock;
-}
-
-/*
- * Should we check a dependency with next one?
- */
-static inline int depend_after(struct held_lock *hlock)
-{
-	return hlock->read != 2 && hlock->check;
-}
-
-/*
- * Check if the xhlock is valid, which would be false if,
- *
- *    1. Has not used after initializaion yet.
- *    2. Got invalidated.
- *
- * Remind hist_lock is implemented as a ring buffer.
- */
-static inline int xhlock_valid(struct hist_lock *xhlock)
-{
-	/*
-	 * xhlock->hlock.instance must be !NULL.
-	 */
-	return !!xhlock->hlock.instance;
-}
-
-/*
- * Record a hist_lock entry.
- *
- * Irq disable is only required.
- */
-static void add_xhlock(struct held_lock *hlock)
-{
-	unsigned int idx = ++current->xhlock_idx;
-	struct hist_lock *xhlock = &xhlock(idx);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-	/*
-	 * This can be done locklessly because they are all task-local
-	 * state, we must however ensure IRQs are disabled.
-	 */
-	WARN_ON_ONCE(!irqs_disabled());
-#endif
-
-	/* Initialize hist_lock's members */
-	xhlock->hlock = *hlock;
-	xhlock->hist_id = ++current->hist_id;
-
-	xhlock->trace.nr_entries = 0;
-	xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES;
-	xhlock->trace.entries = xhlock->trace_entries;
-
-	if (crossrelease_fullstack) {
-		xhlock->trace.skip = 3;
-		save_stack_trace(&xhlock->trace);
-	} else {
-		xhlock->trace.nr_entries = 1;
-		xhlock->trace.entries[0] = hlock->acquire_ip;
-	}
-}
-
-static inline int same_context_xhlock(struct hist_lock *xhlock)
-{
-	return xhlock->hlock.irq_context == task_irq_context(current);
-}
-
-/*
- * This should be lockless as far as possible because this would be
- * called very frequently.
- */
-static void check_add_xhlock(struct held_lock *hlock)
-{
-	/*
-	 * Record a hist_lock, only in case that acquisitions ahead
-	 * could depend on the held_lock. For example, if the held_lock
-	 * is trylock then acquisitions ahead never depends on that.
-	 * In that case, we don't need to record it. Just return.
-	 */
-	if (!current->xhlocks || !depend_before(hlock))
-		return;
-
-	add_xhlock(hlock);
-}
-
-/*
- * For crosslock.
- */
-static int add_xlock(struct held_lock *hlock)
-{
-	struct cross_lock *xlock;
-	unsigned int gen_id;
-
-	if (!graph_lock())
-		return 0;
-
-	xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock;
-
-	/*
-	 * When acquisitions for a crosslock are overlapped, we use
-	 * nr_acquire to perform commit for them, based on cross_gen_id
-	 * of the first acquisition, which allows to add additional
-	 * dependencies.
-	 *
-	 * Moreover, when no acquisition of a crosslock is in progress,
-	 * we should not perform commit because the lock might not exist
-	 * any more, which might cause incorrect memory access. So we
-	 * have to track the number of acquisitions of a crosslock.
-	 *
-	 * depend_after() is necessary to initialize only the first
-	 * valid xlock so that the xlock can be used on its commit.
-	 */
-	if (xlock->nr_acquire++ && depend_after(&xlock->hlock))
-		goto unlock;
-
-	gen_id = (unsigned int)atomic_inc_return(&cross_gen_id);
-	xlock->hlock = *hlock;
-	xlock->hlock.gen_id = gen_id;
-unlock:
-	graph_unlock();
-	return 1;
-}
-
-/*
- * Called for both normal and crosslock acquires. Normal locks will be
- * pushed on the hist_lock queue. Cross locks will record state and
- * stop regular lock_acquire() to avoid being placed on the held_lock
- * stack.
- *
- * Return: 0 - failure;
- *         1 - crosslock, done;
- *         2 - normal lock, continue to held_lock[] ops.
- */
-static int lock_acquire_crosslock(struct held_lock *hlock)
-{
-	/*
-	 *	CONTEXT 1		CONTEXT 2
-	 *	---------		---------
-	 *	lock A (cross)
-	 *	X = atomic_inc_return(&cross_gen_id)
-	 *	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-	 *				Y = atomic_read_acquire(&cross_gen_id)
-	 *				lock B
-	 *
-	 * atomic_read_acquire() is for ordering between A and B,
-	 * IOW, A happens before B, when CONTEXT 2 see Y >= X.
-	 *
-	 * Pairs with atomic_inc_return() in add_xlock().
-	 */
-	hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id);
-
-	if (cross_lock(hlock->instance))
-		return add_xlock(hlock);
-
-	check_add_xhlock(hlock);
-	return 2;
-}
-
-static int copy_trace(struct stack_trace *trace)
-{
-	unsigned long *buf = stack_trace + nr_stack_trace_entries;
-	unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
-	unsigned int nr = min(max_nr, trace->nr_entries);
-
-	trace->nr_entries = nr;
-	memcpy(buf, trace->entries, nr * sizeof(trace->entries[0]));
-	trace->entries = buf;
-	nr_stack_trace_entries += nr;
-
-	if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
-		if (!debug_locks_off_graph_unlock())
-			return 0;
-
-		print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
-		dump_stack();
-
-		return 0;
-	}
-
-	return 1;
-}
-
-static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock)
-{
-	unsigned int xid, pid;
-	u64 chain_key;
-
-	xid = xlock_class(xlock) - lock_classes;
-	chain_key = iterate_chain_key((u64)0, xid);
-	pid = xhlock_class(xhlock) - lock_classes;
-	chain_key = iterate_chain_key(chain_key, pid);
-
-	if (lookup_chain_cache(chain_key))
-		return 1;
-
-	if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context,
-				chain_key))
-		return 0;
-
-	if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1,
-			    &xhlock->trace, copy_trace))
-		return 0;
-
-	return 1;
-}
-
-static void commit_xhlocks(struct cross_lock *xlock)
-{
-	unsigned int cur = current->xhlock_idx;
-	unsigned int prev_hist_id = xhlock(cur).hist_id;
-	unsigned int i;
-
-	if (!graph_lock())
-		return;
-
-	if (xlock->nr_acquire) {
-		for (i = 0; i < MAX_XHLOCKS_NR; i++) {
-			struct hist_lock *xhlock = &xhlock(cur - i);
-
-			if (!xhlock_valid(xhlock))
-				break;
-
-			if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id))
-				break;
-
-			if (!same_context_xhlock(xhlock))
-				break;
-
-			/*
-			 * Filter out the cases where the ring buffer was
-			 * overwritten and the current entry has a bigger
-			 * hist_id than the previous one, which is impossible
-			 * otherwise:
-			 */
-			if (unlikely(before(prev_hist_id, xhlock->hist_id)))
-				break;
-
-			prev_hist_id = xhlock->hist_id;
-
-			/*
-			 * commit_xhlock() returns 0 with graph_lock already
-			 * released if fail.
-			 */
-			if (!commit_xhlock(xlock, xhlock))
-				return;
-		}
-	}
-
-	graph_unlock();
-}
-
-void lock_commit_crosslock(struct lockdep_map *lock)
-{
-	struct cross_lock *xlock;
-	unsigned long flags;
-
-	if (unlikely(!debug_locks || current->lockdep_recursion))
-		return;
-
-	if (!current->xhlocks)
-		return;
-
-	/*
-	 * Do commit hist_locks with the cross_lock, only in case that
-	 * the cross_lock could depend on acquisitions after that.
-	 *
-	 * For example, if the cross_lock does not have the 'check' flag
-	 * then we don't need to check dependencies and commit for that.
-	 * Just skip it. In that case, of course, the cross_lock does
-	 * not depend on acquisitions ahead, either.
-	 *
-	 * WARNING: Don't do that in add_xlock() in advance. When an
-	 * acquisition context is different from the commit context,
-	 * invalid(skipped) cross_lock might be accessed.
-	 */
-	if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-	current->lockdep_recursion = 1;
-	xlock = &((struct lockdep_map_cross *)lock)->xlock;
-	commit_xhlocks(xlock);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_commit_crosslock);
-
-/*
- * Return: 0 - failure;
- *         1 - crosslock, done;
- *         2 - normal lock, continue to held_lock[] ops.
- */
-static int lock_release_crosslock(struct lockdep_map *lock)
-{
-	if (cross_lock(lock)) {
-		if (!graph_lock())
-			return 0;
-		((struct lockdep_map_cross *)lock)->xlock.nr_acquire--;
-		graph_unlock();
-		return 1;
-	}
-	return 2;
-}
-
-static void cross_init(struct lockdep_map *lock, int cross)
-{
-	if (cross)
-		((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0;
-
-	lock->cross = cross;
-
-	/*
-	 * Crossrelease assumes that the ring buffer size of xhlocks
-	 * is aligned with power of 2. So force it on build.
-	 */
-	BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1));
-}
-
-void lockdep_init_task(struct task_struct *task)
-{
-	int i;
-
-	task->xhlock_idx = UINT_MAX;
-	task->hist_id = 0;
-
-	for (i = 0; i < XHLOCK_CTX_NR; i++) {
-		task->xhlock_idx_hist[i] = UINT_MAX;
-		task->hist_id_save[i] = 0;
-	}
-
-	task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR,
-				GFP_KERNEL);
-}
-
-void lockdep_free_task(struct task_struct *task)
-{
-	if (task->xhlocks) {
-		void *tmp = task->xhlocks;
-		/* Diable crossrelease for current */
-		task->xhlocks = NULL;
-		kfree(tmp);
-	}
-}
-#endif
diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
index 1fd1a7543cdd..936f3d14dd6b 100644
--- a/kernel/locking/spinlock.c
+++ b/kernel/locking/spinlock.c
@@ -66,12 +66,8 @@ void __lockfunc __raw_##op##_lock(locktype##_t *lock)			\
 			break;						\
 		preempt_enable();					\
 									\
-		if (!(lock)->break_lock)				\
-			(lock)->break_lock = 1;				\
-		while ((lock)->break_lock)				\
-			arch_##op##_relax(&lock->raw_lock);		\
+		arch_##op##_relax(&lock->raw_lock);			\
 	}								\
-	(lock)->break_lock = 0;						\
 }									\
 									\
 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)	\
@@ -86,12 +82,9 @@ unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)	\
 		local_irq_restore(flags);				\
 		preempt_enable();					\
 									\
-		if (!(lock)->break_lock)				\
-			(lock)->break_lock = 1;				\
-		while ((lock)->break_lock)				\
-			arch_##op##_relax(&lock->raw_lock);		\
+		arch_##op##_relax(&lock->raw_lock);			\
 	}								\
-	(lock)->break_lock = 0;						\
+									\
 	return flags;							\
 }									\
 									\