locking: Move the mutex code to kernel/locking/

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-1ditvncg30dgbpvrz2bxfmke@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 960 deletions

diff --git a/kernel/mutex.c b/kernel/mutex.c
deleted file mode 100644
index d24105b1b794..000000000000
--- a/kernel/mutex.c
+++ /dev/null
@@ -1,960 +0,0 @@
-/*
- * kernel/mutex.c
- *
- * Mutexes: blocking mutual exclusion locks
- *
- * Started by Ingo Molnar:
- *
- *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
- * David Howells for suggestions and improvements.
- *
- *  - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
- *    from the -rt tree, where it was originally implemented for rtmutexes
- *    by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
- *    and Sven Dietrich.
- *
- * Also see Documentation/mutex-design.txt.
- */
-#include <linux/mutex.h>
-#include <linux/ww_mutex.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-
-/*
- * In the DEBUG case we are using the "NULL fastpath" for mutexes,
- * which forces all calls into the slowpath:
- */
-#ifdef CONFIG_DEBUG_MUTEXES
-# include "mutex-debug.h"
-# include <asm-generic/mutex-null.h>
-#else
-# include "mutex.h"
-# include <asm/mutex.h>
-#endif
-
-/*
- * A negative mutex count indicates that waiters are sleeping waiting for the
- * mutex.
- */
-#define	MUTEX_SHOW_NO_WAITER(mutex)	(atomic_read(&(mutex)->count) >= 0)
-
-void
-__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
-{
-	atomic_set(&lock->count, 1);
-	spin_lock_init(&lock->wait_lock);
-	INIT_LIST_HEAD(&lock->wait_list);
-	mutex_clear_owner(lock);
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-	lock->spin_mlock = NULL;
-#endif
-
-	debug_mutex_init(lock, name, key);
-}
-
-EXPORT_SYMBOL(__mutex_init);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * We split the mutex lock/unlock logic into separate fastpath and
- * slowpath functions, to reduce the register pressure on the fastpath.
- * We also put the fastpath first in the kernel image, to make sure the
- * branch is predicted by the CPU as default-untaken.
- */
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_lock - acquire the mutex
- * @lock: the mutex to be acquired
- *
- * Lock the mutex exclusively for this task. If the mutex is not
- * available right now, it will sleep until it can get it.
- *
- * The mutex must later on be released by the same task that
- * acquired it. Recursive locking is not allowed. The task
- * may not exit without first unlocking the mutex. Also, kernel
- * memory where the mutex resides mutex must not be freed with
- * the mutex still locked. The mutex must first be initialized
- * (or statically defined) before it can be locked. memset()-ing
- * the mutex to 0 is not allowed.
- *
- * ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging
- *   checks that will enforce the restrictions and will also do
- *   deadlock debugging. )
- *
- * This function is similar to (but not equivalent to) down().
- */
-void __sched mutex_lock(struct mutex *lock)
-{
-	might_sleep();
-	/*
-	 * The locking fastpath is the 1->0 transition from
-	 * 'unlocked' into 'locked' state.
-	 */
-	__mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
-	mutex_set_owner(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock);
-#endif
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * In order to avoid a stampede of mutex spinners from acquiring the mutex
- * more or less simultaneously, the spinners need to acquire a MCS lock
- * first before spinning on the owner field.
- *
- * We don't inline mspin_lock() so that perf can correctly account for the
- * time spent in this lock function.
- */
-struct mspin_node {
-	struct mspin_node *next ;
-	int		  locked;	/* 1 if lock acquired */
-};
-#define	MLOCK(mutex)	((struct mspin_node **)&((mutex)->spin_mlock))
-
-static noinline
-void mspin_lock(struct mspin_node **lock, struct mspin_node *node)
-{
-	struct mspin_node *prev;
-
-	/* Init node */
-	node->locked = 0;
-	node->next   = NULL;
-
-	prev = xchg(lock, node);
-	if (likely(prev == NULL)) {
-		/* Lock acquired */
-		node->locked = 1;
-		return;
-	}
-	ACCESS_ONCE(prev->next) = node;
-	smp_wmb();
-	/* Wait until the lock holder passes the lock down */
-	while (!ACCESS_ONCE(node->locked))
-		arch_mutex_cpu_relax();
-}
-
-static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node)
-{
-	struct mspin_node *next = ACCESS_ONCE(node->next);
-
-	if (likely(!next)) {
-		/*
-		 * Release the lock by setting it to NULL
-		 */
-		if (cmpxchg(lock, node, NULL) == node)
-			return;
-		/* Wait until the next pointer is set */
-		while (!(next = ACCESS_ONCE(node->next)))
-			arch_mutex_cpu_relax();
-	}
-	ACCESS_ONCE(next->locked) = 1;
-	smp_wmb();
-}
-
-/*
- * Mutex spinning code migrated from kernel/sched/core.c
- */
-
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
-	if (lock->owner != owner)
-		return false;
-
-	/*
-	 * Ensure we emit the owner->on_cpu, dereference _after_ checking
-	 * lock->owner still matches owner, if that fails, owner might
-	 * point to free()d memory, if it still matches, the rcu_read_lock()
-	 * ensures the memory stays valid.
-	 */
-	barrier();
-
-	return owner->on_cpu;
-}
-
-/*
- * Look out! "owner" is an entirely speculative pointer
- * access and not reliable.
- */
-static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
-{
-	rcu_read_lock();
-	while (owner_running(lock, owner)) {
-		if (need_resched())
-			break;
-
-		arch_mutex_cpu_relax();
-	}
-	rcu_read_unlock();
-
-	/*
-	 * We break out the loop above on need_resched() and when the
-	 * owner changed, which is a sign for heavy contention. Return
-	 * success only when lock->owner is NULL.
-	 */
-	return lock->owner == NULL;
-}
-
-/*
- * Initial check for entering the mutex spinning loop
- */
-static inline int mutex_can_spin_on_owner(struct mutex *lock)
-{
-	struct task_struct *owner;
-	int retval = 1;
-
-	rcu_read_lock();
-	owner = ACCESS_ONCE(lock->owner);
-	if (owner)
-		retval = owner->on_cpu;
-	rcu_read_unlock();
-	/*
-	 * if lock->owner is not set, the mutex owner may have just acquired
-	 * it and not set the owner yet or the mutex has been released.
-	 */
-	return retval;
-}
-#endif
-
-static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_unlock - release the mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a not locked mutex is not allowed.
- *
- * This function is similar to (but not equivalent to) up().
- */
-void __sched mutex_unlock(struct mutex *lock)
-{
-	/*
-	 * The unlocking fastpath is the 0->1 transition from 'locked'
-	 * into 'unlocked' state:
-	 */
-#ifndef CONFIG_DEBUG_MUTEXES
-	/*
-	 * When debugging is enabled we must not clear the owner before time,
-	 * the slow path will always be taken, and that clears the owner field
-	 * after verifying that it was indeed current.
-	 */
-	mutex_clear_owner(lock);
-#endif
-	__mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
-}
-
-EXPORT_SYMBOL(mutex_unlock);
-
-/**
- * ww_mutex_unlock - release the w/w mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously with any of the
- * ww_mutex_lock* functions (with or without an acquire context). It is
- * forbidden to release the locks after releasing the acquire context.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a unlocked mutex is not allowed.
- */
-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;
-	}
-
-#ifndef CONFIG_DEBUG_MUTEXES
-	/*
-	 * When debugging is enabled we must not clear the owner before time,
-	 * the slow path will always be taken, and that clears the owner field
-	 * after verifying that it was indeed current.
-	 */
-	mutex_clear_owner(&lock->base);
-#endif
-	__mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
-}
-EXPORT_SYMBOL(ww_mutex_unlock);
-
-static inline int __sched
-__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-	struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
-
-	if (!hold_ctx)
-		return 0;
-
-	if (unlikely(ctx == hold_ctx))
-		return -EALREADY;
-
-	if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
-	    (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
-#ifdef CONFIG_DEBUG_MUTEXES
-		DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
-		ctx->contending_lock = ww;
-#endif
-		return -EDEADLK;
-	}
-
-	return 0;
-}
-
-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);
-
-	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++;
-}
-
-/*
- * after acquiring lock with fastpath or when we lost out in contested
- * slowpath, set ctx and wake up any waiters so they can recheck.
- *
- * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
- * as the fastpath and opportunistic spinning are disabled in that case.
- */
-static __always_inline void
-ww_mutex_set_context_fastpath(struct ww_mutex *lock,
-			       struct ww_acquire_ctx *ctx)
-{
-	unsigned long flags;
-	struct mutex_waiter *cur;
-
-	ww_mutex_lock_acquired(lock, ctx);
-
-	lock->ctx = ctx;
-
-	/*
-	 * The lock->ctx update should be visible on all cores before
-	 * the atomic read 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(); /* ^^^ */
-
-	/*
-	 * Check if lock is contended, if not there is nobody to wake up
-	 */
-	if (likely(atomic_read(&lock->base.count) == 0))
-		return;
-
-	/*
-	 * Uh oh, we raced in fastpath, wake up everyone in this case,
-	 * so they can see the new lock->ctx.
-	 */
-	spin_lock_mutex(&lock->base.wait_lock, flags);
-	list_for_each_entry(cur, &lock->base.wait_list, list) {
-		debug_mutex_wake_waiter(&lock->base, cur);
-		wake_up_process(cur->task);
-	}
-	spin_unlock_mutex(&lock->base.wait_lock, flags);
-}
-
-/*
- * Lock a mutex (possibly interruptible), slowpath:
- */
-static __always_inline int __sched
-__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
-		    struct lockdep_map *nest_lock, unsigned long ip,
-		    struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
-{
-	struct task_struct *task = current;
-	struct mutex_waiter waiter;
-	unsigned long flags;
-	int ret;
-
-	preempt_disable();
-	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-	/*
-	 * Optimistic spinning.
-	 *
-	 * We try to spin for acquisition when we find that there are no
-	 * pending waiters and the lock owner is currently running on a
-	 * (different) CPU.
-	 *
-	 * The rationale is that if the lock owner is running, it is likely to
-	 * release the lock soon.
-	 *
-	 * Since this needs the lock owner, and this mutex implementation
-	 * doesn't track the owner atomically in the lock field, we need to
-	 * track it non-atomically.
-	 *
-	 * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
-	 * to serialize everything.
-	 *
-	 * The mutex spinners are queued up using MCS lock so that only one
-	 * spinner can compete for the mutex. However, if mutex spinning isn't
-	 * going to happen, there is no point in going through the lock/unlock
-	 * overhead.
-	 */
-	if (!mutex_can_spin_on_owner(lock))
-		goto slowpath;
-
-	for (;;) {
-		struct task_struct *owner;
-		struct mspin_node  node;
-
-		if (use_ww_ctx && ww_ctx->acquired > 0) {
-			struct ww_mutex *ww;
-
-			ww = container_of(lock, struct ww_mutex, base);
-			/*
-			 * If ww->ctx is set the contents are undefined, only
-			 * by acquiring wait_lock there is a guarantee that
-			 * they are not invalid when reading.
-			 *
-			 * As such, when deadlock detection needs to be
-			 * performed the optimistic spinning cannot be done.
-			 */
-			if (ACCESS_ONCE(ww->ctx))
-				goto slowpath;
-		}
-
-		/*
-		 * If there's an owner, wait for it to either
-		 * release the lock or go to sleep.
-		 */
-		mspin_lock(MLOCK(lock), &node);
-		owner = ACCESS_ONCE(lock->owner);
-		if (owner && !mutex_spin_on_owner(lock, owner)) {
-			mspin_unlock(MLOCK(lock), &node);
-			goto slowpath;
-		}
-
-		if ((atomic_read(&lock->count) == 1) &&
-		    (atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
-			lock_acquired(&lock->dep_map, ip);
-			if (use_ww_ctx) {
-				struct ww_mutex *ww;
-				ww = container_of(lock, struct ww_mutex, base);
-
-				ww_mutex_set_context_fastpath(ww, ww_ctx);
-			}
-
-			mutex_set_owner(lock);
-			mspin_unlock(MLOCK(lock), &node);
-			preempt_enable();
-			return 0;
-		}
-		mspin_unlock(MLOCK(lock), &node);
-
-		/*
-		 * When there's no owner, we might have preempted between the
-		 * owner acquiring the lock and setting the owner field. If
-		 * we're an RT task that will live-lock because we won't let
-		 * the owner complete.
-		 */
-		if (!owner && (need_resched() || rt_task(task)))
-			goto slowpath;
-
-		/*
-		 * The cpu_relax() call is a compiler barrier which forces
-		 * everything in this loop to be re-loaded. We don't need
-		 * memory barriers as we'll eventually observe the right
-		 * values at the cost of a few extra spins.
-		 */
-		arch_mutex_cpu_relax();
-	}
-slowpath:
-#endif
-	spin_lock_mutex(&lock->wait_lock, flags);
-
-	/* once more, can we acquire the lock? */
-	if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
-		goto skip_wait;
-
-	debug_mutex_lock_common(lock, &waiter);
-	debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
-
-	/* add waiting tasks to the end of the waitqueue (FIFO): */
-	list_add_tail(&waiter.list, &lock->wait_list);
-	waiter.task = task;
-
-	lock_contended(&lock->dep_map, ip);
-
-	for (;;) {
-		/*
-		 * Lets try to take the lock again - this is needed even if
-		 * we get here for the first time (shortly after failing to
-		 * acquire the lock), to make sure that we get a wakeup once
-		 * it's unlocked. Later on, if we sleep, this is the
-		 * operation that gives us the lock. We xchg it to -1, so
-		 * that when we release the lock, we properly wake up the
-		 * other waiters:
-		 */
-		if (MUTEX_SHOW_NO_WAITER(lock) &&
-		    (atomic_xchg(&lock->count, -1) == 1))
-			break;
-
-		/*
-		 * got a signal? (This code gets eliminated in the
-		 * TASK_UNINTERRUPTIBLE case.)
-		 */
-		if (unlikely(signal_pending_state(state, task))) {
-			ret = -EINTR;
-			goto err;
-		}
-
-		if (use_ww_ctx && ww_ctx->acquired > 0) {
-			ret = __mutex_lock_check_stamp(lock, ww_ctx);
-			if (ret)
-				goto err;
-		}
-
-		__set_task_state(task, state);
-
-		/* didn't get the lock, go to sleep: */
-		spin_unlock_mutex(&lock->wait_lock, flags);
-		schedule_preempt_disabled();
-		spin_lock_mutex(&lock->wait_lock, flags);
-	}
-	mutex_remove_waiter(lock, &waiter, current_thread_info());
-	/* set it to 0 if there are no waiters left: */
-	if (likely(list_empty(&lock->wait_list)))
-		atomic_set(&lock->count, 0);
-	debug_mutex_free_waiter(&waiter);
-
-skip_wait:
-	/* got the lock - cleanup and rejoice! */
-	lock_acquired(&lock->dep_map, ip);
-	mutex_set_owner(lock);
-
-	if (use_ww_ctx) {
-		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-		struct mutex_waiter *cur;
-
-		/*
-		 * This branch gets optimized out for the common case,
-		 * and is only important for ww_mutex_lock.
-		 */
-		ww_mutex_lock_acquired(ww, ww_ctx);
-		ww->ctx = ww_ctx;
-
-		/*
-		 * Give any possible sleeping processes the chance to wake up,
-		 * so they can recheck if they have to back off.
-		 */
-		list_for_each_entry(cur, &lock->wait_list, list) {
-			debug_mutex_wake_waiter(lock, cur);
-			wake_up_process(cur->task);
-		}
-	}
-
-	spin_unlock_mutex(&lock->wait_lock, flags);
-	preempt_enable();
-	return 0;
-
-err:
-	mutex_remove_waiter(lock, &waiter, task_thread_info(task));
-	spin_unlock_mutex(&lock->wait_lock, flags);
-	debug_mutex_free_waiter(&waiter);
-	mutex_release(&lock->dep_map, 1, ip);
-	preempt_enable();
-	return ret;
-}
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void __sched
-mutex_lock_nested(struct mutex *lock, unsigned int subclass)
-{
-	might_sleep();
-	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
-			    subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_nested);
-
-void __sched
-_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
-{
-	might_sleep();
-	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
-			    0, nest, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
-
-int __sched
-mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
-{
-	might_sleep();
-	return __mutex_lock_common(lock, TASK_KILLABLE,
-				   subclass, NULL, _RET_IP_, NULL, 0);
-}
-EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
-
-int __sched
-mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
-{
-	might_sleep();
-	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
-				   subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
-
-static inline int
-ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
-	unsigned tmp;
-
-	if (ctx->deadlock_inject_countdown-- == 0) {
-		tmp = ctx->deadlock_inject_interval;
-		if (tmp > UINT_MAX/4)
-			tmp = UINT_MAX;
-		else
-			tmp = tmp*2 + tmp + tmp/2;
-
-		ctx->deadlock_inject_interval = tmp;
-		ctx->deadlock_inject_countdown = tmp;
-		ctx->contending_lock = lock;
-
-		ww_mutex_unlock(lock);
-
-		return -EDEADLK;
-	}
-#endif
-
-	return 0;
-}
-
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	int ret;
-
-	might_sleep();
-	ret =  __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
-				   0, &ctx->dep_map, _RET_IP_, ctx, 1);
-	if (!ret && ctx->acquired > 1)
-		return ww_mutex_deadlock_injection(lock, ctx);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	int ret;
-
-	might_sleep();
-	ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
-				  0, &ctx->dep_map, _RET_IP_, ctx, 1);
-
-	if (!ret && ctx->acquired > 1)
-		return ww_mutex_deadlock_injection(lock, ctx);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/*
- * Release the lock, slowpath:
- */
-static inline void
-__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
-{
-	struct mutex *lock = container_of(lock_count, struct mutex, count);
-	unsigned long flags;
-
-	spin_lock_mutex(&lock->wait_lock, flags);
-	mutex_release(&lock->dep_map, nested, _RET_IP_);
-	debug_mutex_unlock(lock);
-
-	/*
-	 * some architectures leave the lock unlocked in the fastpath failure
-	 * case, others need to leave it locked. In the later case we have to
-	 * unlock it here
-	 */
-	if (__mutex_slowpath_needs_to_unlock())
-		atomic_set(&lock->count, 1);
-
-	if (!list_empty(&lock->wait_list)) {
-		/* get the first entry from the wait-list: */
-		struct mutex_waiter *waiter =
-				list_entry(lock->wait_list.next,
-					   struct mutex_waiter, list);
-
-		debug_mutex_wake_waiter(lock, waiter);
-
-		wake_up_process(waiter->task);
-	}
-
-	spin_unlock_mutex(&lock->wait_lock, flags);
-}
-
-/*
- * Release the lock, slowpath:
- */
-static __used noinline void
-__mutex_unlock_slowpath(atomic_t *lock_count)
-{
-	__mutex_unlock_common_slowpath(lock_count, 1);
-}
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * Here come the less common (and hence less performance-critical) APIs:
- * mutex_lock_interruptible() and mutex_trylock().
- */
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock);
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock);
-
-/**
- * mutex_lock_interruptible - acquire the mutex, interruptible
- * @lock: the mutex to be acquired
- *
- * Lock the mutex like mutex_lock(), and return 0 if the mutex has
- * been acquired or sleep until the mutex becomes available. If a
- * signal arrives while waiting for the lock then this function
- * returns -EINTR.
- *
- * This function is similar to (but not equivalent to) down_interruptible().
- */
-int __sched mutex_lock_interruptible(struct mutex *lock)
-{
-	int ret;
-
-	might_sleep();
-	ret =  __mutex_fastpath_lock_retval(&lock->count);
-	if (likely(!ret)) {
-		mutex_set_owner(lock);
-		return 0;
-	} else
-		return __mutex_lock_interruptible_slowpath(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock_interruptible);
-
-int __sched mutex_lock_killable(struct mutex *lock)
-{
-	int ret;
-
-	might_sleep();
-	ret = __mutex_fastpath_lock_retval(&lock->count);
-	if (likely(!ret)) {
-		mutex_set_owner(lock);
-		return 0;
-	} else
-		return __mutex_lock_killable_slowpath(lock);
-}
-EXPORT_SYMBOL(mutex_lock_killable);
-
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
-{
-	struct mutex *lock = container_of(lock_count, struct mutex, count);
-
-	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
-			    NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock)
-{
-	return __mutex_lock_common(lock, TASK_KILLABLE, 0,
-				   NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock)
-{
-	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
-				   NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
-				   NULL, _RET_IP_, ctx, 1);
-}
-
-static noinline int __sched
-__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
-					    struct ww_acquire_ctx *ctx)
-{
-	return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
-				   NULL, _RET_IP_, ctx, 1);
-}
-
-#endif
-
-/*
- * Spinlock based trylock, we take the spinlock and check whether we
- * can get the lock:
- */
-static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
-{
-	struct mutex *lock = container_of(lock_count, struct mutex, count);
-	unsigned long flags;
-	int prev;
-
-	spin_lock_mutex(&lock->wait_lock, flags);
-
-	prev = atomic_xchg(&lock->count, -1);
-	if (likely(prev == 1)) {
-		mutex_set_owner(lock);
-		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
-	}
-
-	/* Set it back to 0 if there are no waiters: */
-	if (likely(list_empty(&lock->wait_list)))
-		atomic_set(&lock->count, 0);
-
-	spin_unlock_mutex(&lock->wait_lock, flags);
-
-	return prev == 1;
-}
-
-/**
- * mutex_trylock - try to acquire the mutex, without waiting
- * @lock: the mutex to be acquired
- *
- * Try to acquire the mutex atomically. Returns 1 if the mutex
- * has been acquired successfully, and 0 on contention.
- *
- * NOTE: this function follows the spin_trylock() convention, so
- * it is negated from the down_trylock() return values! Be careful
- * about this when converting semaphore users to mutexes.
- *
- * This function must not be used in interrupt context. The
- * mutex must be released by the same task that acquired it.
- */
-int __sched mutex_trylock(struct mutex *lock)
-{
-	int ret;
-
-	ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
-	if (ret)
-		mutex_set_owner(lock);
-
-	return ret;
-}
-EXPORT_SYMBOL(mutex_trylock);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	int ret;
-
-	might_sleep();
-
-	ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
-	if (likely(!ret)) {
-		ww_mutex_set_context_fastpath(lock, ctx);
-		mutex_set_owner(&lock->base);
-	} else
-		ret = __ww_mutex_lock_slowpath(lock, ctx);
-	return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	int ret;
-
-	might_sleep();
-
-	ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
-	if (likely(!ret)) {
-		ww_mutex_set_context_fastpath(lock, ctx);
-		mutex_set_owner(&lock->base);
-	} else
-		ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
-	return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/**
- * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
- * @cnt: the atomic which we are to dec
- * @lock: the mutex to return holding if we dec to 0
- *
- * return true and hold lock if we dec to 0, return false otherwise
- */
-int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
-{
-	/* dec if we can't possibly hit 0 */
-	if (atomic_add_unless(cnt, -1, 1))
-		return 0;
-	/* we might hit 0, so take the lock */
-	mutex_lock(lock);
-	if (!atomic_dec_and_test(cnt)) {
-		/* when we actually did the dec, we didn't hit 0 */
-		mutex_unlock(lock);
-		return 0;
-	}
-	/* we hit 0, and we hold the lock */
-	return 1;
-}
-EXPORT_SYMBOL(atomic_dec_and_mutex_lock);