mutex: Move ww_mutex definitions to ww_mutex.h

Move the definitions for wound/wait mutexes out to a separate
header, ww_mutex.h. This reduces clutter in mutex.h, and
increases readability.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Dave Airlie <airlied@gmail.com>
Link: http://lkml.kernel.org/r/51D675DC.3000907@canonical.com
[ Tidied up the code a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 358 deletions

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 3793ed7feeeb..ccd4260834c5 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -78,40 +78,6 @@ struct mutex_waiter {
 #endif
 };
 
-struct ww_class {
-	atomic_long_t stamp;
-	struct lock_class_key acquire_key;
-	struct lock_class_key mutex_key;
-	const char *acquire_name;
-	const char *mutex_name;
-};
-
-struct ww_acquire_ctx {
-	struct task_struct *task;
-	unsigned long stamp;
-	unsigned acquired;
-#ifdef CONFIG_DEBUG_MUTEXES
-	unsigned done_acquire;
-	struct ww_class *ww_class;
-	struct ww_mutex *contending_lock;
-#endif
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	struct lockdep_map dep_map;
-#endif
-#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
-	unsigned deadlock_inject_interval;
-	unsigned deadlock_inject_countdown;
-#endif
-};
-
-struct ww_mutex {
-	struct mutex base;
-	struct ww_acquire_ctx *ctx;
-#ifdef CONFIG_DEBUG_MUTEXES
-	struct ww_class *ww_class;
-#endif
-};
-
 #ifdef CONFIG_DEBUG_MUTEXES
 # include <linux/mutex-debug.h>
 #else
@@ -136,11 +102,8 @@ static inline void mutex_destroy(struct mutex *lock) {}
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
 		, .dep_map = { .name = #lockname }
-# define __WW_CLASS_MUTEX_INITIALIZER(lockname, ww_class) \
-		, .ww_class = &ww_class
 #else
 # define __DEP_MAP_MUTEX_INITIALIZER(lockname)
-# define __WW_CLASS_MUTEX_INITIALIZER(lockname, ww_class)
 #endif
 
 #define __MUTEX_INITIALIZER(lockname) \
@@ -150,49 +113,13 @@ static inline void mutex_destroy(struct mutex *lock) {}
 		__DEBUG_MUTEX_INITIALIZER(lockname) \
 		__DEP_MAP_MUTEX_INITIALIZER(lockname) }
 
-#define __WW_CLASS_INITIALIZER(ww_class) \
-		{ .stamp = ATOMIC_LONG_INIT(0) \
-		, .acquire_name = #ww_class "_acquire" \
-		, .mutex_name = #ww_class "_mutex" }
-
-#define __WW_MUTEX_INITIALIZER(lockname, class) \
-		{ .base = { \__MUTEX_INITIALIZER(lockname) } \
-		__WW_CLASS_MUTEX_INITIALIZER(lockname, class) }
-
 #define DEFINE_MUTEX(mutexname) \
 	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
 
-#define DEFINE_WW_CLASS(classname) \
-	struct ww_class classname = __WW_CLASS_INITIALIZER(classname)
-
-#define DEFINE_WW_MUTEX(mutexname, ww_class) \
-	struct ww_mutex mutexname = __WW_MUTEX_INITIALIZER(mutexname, ww_class)
-
-
 extern void __mutex_init(struct mutex *lock, const char *name,
 			 struct lock_class_key *key);
 
 /**
- * ww_mutex_init - initialize the w/w mutex
- * @lock: the mutex to be initialized
- * @ww_class: the w/w class the mutex should belong to
- *
- * Initialize the w/w mutex to unlocked state and associate it with the given
- * class.
- *
- * It is not allowed to initialize an already locked mutex.
- */
-static inline void ww_mutex_init(struct ww_mutex *lock,
-				 struct ww_class *ww_class)
-{
-	__mutex_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
-	lock->ctx = NULL;
-#ifdef CONFIG_DEBUG_MUTEXES
-	lock->ww_class = ww_class;
-#endif
-}
-
-/**
  * mutex_is_locked - is the mutex locked
  * @lock: the mutex to be queried
  *
@@ -246,291 +173,6 @@ extern int __must_check mutex_lock_killable(struct mutex *lock);
 extern int mutex_trylock(struct mutex *lock);
 extern void mutex_unlock(struct mutex *lock);
 
-/**
- * ww_acquire_init - initialize a w/w acquire context
- * @ctx: w/w acquire context to initialize
- * @ww_class: w/w class of the context
- *
- * Initializes an context to acquire multiple mutexes of the given w/w class.
- *
- * Context-based w/w mutex acquiring can be done in any order whatsoever within
- * a given lock class. Deadlocks will be detected and handled with the
- * wait/wound logic.
- *
- * Mixing of context-based w/w mutex acquiring and single w/w mutex locking can
- * result in undetected deadlocks and is so forbidden. Mixing different contexts
- * for the same w/w class when acquiring mutexes can also result in undetected
- * deadlocks, and is hence also forbidden. Both types of abuse will be caught by
- * enabling CONFIG_PROVE_LOCKING.
- *
- * Nesting of acquire contexts for _different_ w/w classes is possible, subject
- * to the usual locking rules between different lock classes.
- *
- * An acquire context must be released with ww_acquire_fini by the same task
- * before the memory is freed. It is recommended to allocate the context itself
- * on the stack.
- */
-static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
-				   struct ww_class *ww_class)
-{
-	ctx->task = current;
-	ctx->stamp = atomic_long_inc_return(&ww_class->stamp);
-	ctx->acquired = 0;
-#ifdef CONFIG_DEBUG_MUTEXES
-	ctx->ww_class = ww_class;
-	ctx->done_acquire = 0;
-	ctx->contending_lock = NULL;
-#endif
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	debug_check_no_locks_freed((void *)ctx, sizeof(*ctx));
-	lockdep_init_map(&ctx->dep_map, ww_class->acquire_name,
-			 &ww_class->acquire_key, 0);
-	mutex_acquire(&ctx->dep_map, 0, 0, _RET_IP_);
-#endif
-#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
-	ctx->deadlock_inject_interval = 1;
-	ctx->deadlock_inject_countdown = ctx->stamp & 0xf;
-#endif
-}
-
-/**
- * ww_acquire_done - marks the end of the acquire phase
- * @ctx: the acquire context
- *
- * Marks the end of the acquire phase, any further w/w mutex lock calls using
- * this context are forbidden.
- *
- * Calling this function is optional, it is just useful to document w/w mutex
- * code and clearly designated the acquire phase from actually using the locked
- * data structures.
- */
-static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
-	lockdep_assert_held(ctx);
-
-	DEBUG_LOCKS_WARN_ON(ctx->done_acquire);
-	ctx->done_acquire = 1;
-#endif
-}
-
-/**
- * ww_acquire_fini - releases a w/w acquire context
- * @ctx: the acquire context to free
- *
- * Releases a w/w acquire context. This must be called _after_ all acquired w/w
- * mutexes have been released with ww_mutex_unlock.
- */
-static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
-	mutex_release(&ctx->dep_map, 0, _THIS_IP_);
-
-	DEBUG_LOCKS_WARN_ON(ctx->acquired);
-	if (!config_enabled(CONFIG_PROVE_LOCKING))
-		/*
-		 * lockdep will normally handle this,
-		 * but fail without anyway
-		 */
-		ctx->done_acquire = 1;
-
-	if (!config_enabled(CONFIG_DEBUG_LOCK_ALLOC))
-		/* ensure ww_acquire_fini will still fail if called twice */
-		ctx->acquired = ~0U;
-#endif
-}
-
-extern int __must_check __ww_mutex_lock(struct ww_mutex *lock,
-					struct ww_acquire_ctx *ctx);
-extern int __must_check __ww_mutex_lock_interruptible(struct ww_mutex *lock,
-						      struct ww_acquire_ctx *ctx);
-
-/**
- * ww_mutex_lock - acquire the w/w mutex
- * @lock: the mutex to be acquired
- * @ctx: w/w acquire context, or NULL to acquire only a single lock.
- *
- * Lock the w/w mutex exclusively for this task.
- *
- * Deadlocks within a given w/w class of locks are detected and handled with the
- * wait/wound algorithm. If the lock isn't immediately avaiable this function
- * will either sleep until it is (wait case). Or it selects the current context
- * for backing off by returning -EDEADLK (wound case). Trying to acquire the
- * same lock with the same context twice is also detected and signalled by
- * returning -EALREADY. Returns 0 if the mutex was successfully acquired.
- *
- * In the wound case the caller must release all currently held w/w mutexes for
- * the given context and then wait for this contending lock to be available by
- * calling ww_mutex_lock_slow. Alternatively callers can opt to not acquire this
- * lock and proceed with trying to acquire further w/w mutexes (e.g. when
- * scanning through lru lists trying to free resources).
- *
- * The mutex must later on be released by the same task that
- * acquired it. The task may not exit without first unlocking the mutex. Also,
- * kernel memory where the mutex resides 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 mutex must be
- * of the same w/w lock class as was used to initialize the acquire context.
- *
- * A mutex acquired with this function must be released with ww_mutex_unlock.
- */
-static inline int ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	if (ctx)
-		return __ww_mutex_lock(lock, ctx);
-	else {
-		mutex_lock(&lock->base);
-		return 0;
-	}
-}
-
-/**
- * ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
- * @lock: the mutex to be acquired
- * @ctx: w/w acquire context
- *
- * Lock the w/w mutex exclusively for this task.
- *
- * Deadlocks within a given w/w class of locks are detected and handled with the
- * wait/wound algorithm. If the lock isn't immediately avaiable this function
- * will either sleep until it is (wait case). Or it selects the current context
- * for backing off by returning -EDEADLK (wound case). Trying to acquire the
- * same lock with the same context twice is also detected and signalled by
- * returning -EALREADY. Returns 0 if the mutex was successfully acquired. If a
- * signal arrives while waiting for the lock then this function returns -EINTR.
- *
- * In the wound case the caller must release all currently held w/w mutexes for
- * the given context and then wait for this contending lock to be available by
- * calling ww_mutex_lock_slow_interruptible. Alternatively callers can opt to
- * not acquire this lock and proceed with trying to acquire further w/w mutexes
- * (e.g. when scanning through lru lists trying to free resources).
- *
- * The mutex must later on be released by the same task that
- * acquired it. The task may not exit without first unlocking the mutex. Also,
- * kernel memory where the mutex resides 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 mutex must be
- * of the same w/w lock class as was used to initialize the acquire context.
- *
- * A mutex acquired with this function must be released with ww_mutex_unlock.
- */
-static inline int __must_check ww_mutex_lock_interruptible(struct ww_mutex *lock,
-							   struct ww_acquire_ctx *ctx)
-{
-	if (ctx)
-		return __ww_mutex_lock_interruptible(lock, ctx);
-	else
-		return mutex_lock_interruptible(&lock->base);
-}
-
-/**
- * ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
- * @lock: the mutex to be acquired
- * @ctx: w/w acquire context
- *
- * Acquires a w/w mutex with the given context after a wound case. This function
- * will sleep until the lock becomes available.
- *
- * The caller must have released all w/w mutexes already acquired with the
- * context and then call this function on the contended lock.
- *
- * Afterwards the caller may continue to (re)acquire the other w/w mutexes it
- * needs with ww_mutex_lock. Note that the -EALREADY return code from
- * ww_mutex_lock can be used to avoid locking this contended mutex twice.
- *
- * It is forbidden to call this function with any other w/w mutexes associated
- * with the context held. It is forbidden to call this on anything else than the
- * contending mutex.
- *
- * Note that the slowpath lock acquiring can also be done by calling
- * ww_mutex_lock directly. This function here is simply to help w/w mutex
- * locking code readability by clearly denoting the slowpath.
- */
-static inline void
-ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-	int ret;
-#ifdef CONFIG_DEBUG_MUTEXES
-	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
-#endif
-	ret = ww_mutex_lock(lock, ctx);
-	(void)ret;
-}
-
-/**
- * ww_mutex_lock_slow_interruptible - slowpath acquiring of the w/w mutex,
- * 				      interruptible
- * @lock: the mutex to be acquired
- * @ctx: w/w acquire context
- *
- * Acquires a w/w mutex with the given context after a wound case. This function
- * will sleep until the lock becomes available and returns 0 when the lock has
- * been acquired. If a signal arrives while waiting for the lock then this
- * function returns -EINTR.
- *
- * The caller must have released all w/w mutexes already acquired with the
- * context and then call this function on the contended lock.
- *
- * Afterwards the caller may continue to (re)acquire the other w/w mutexes it
- * needs with ww_mutex_lock. Note that the -EALREADY return code from
- * ww_mutex_lock can be used to avoid locking this contended mutex twice.
- *
- * It is forbidden to call this function with any other w/w mutexes associated
- * with the given context held. It is forbidden to call this on anything else
- * than the contending mutex.
- *
- * Note that the slowpath lock acquiring can also be done by calling
- * ww_mutex_lock_interruptible directly. This function here is simply to help
- * w/w mutex locking code readability by clearly denoting the slowpath.
- */
-static inline int __must_check
-ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
-				 struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
-	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
-#endif
-	return ww_mutex_lock_interruptible(lock, ctx);
-}
-
-extern void ww_mutex_unlock(struct ww_mutex *lock);
-
-/**
- * ww_mutex_trylock - tries to acquire the w/w mutex without acquire context
- * @lock: mutex to lock
- *
- * Trylocks a mutex without acquire context, so no deadlock detection is
- * possible. Returns 1 if the mutex has been acquired successfully, 0 otherwise.
- */
-static inline int __must_check ww_mutex_trylock(struct ww_mutex *lock)
-{
-	return mutex_trylock(&lock->base);
-}
-
-/***
- * ww_mutex_destroy - mark a w/w mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-static inline void ww_mutex_destroy(struct ww_mutex *lock)
-{
-	mutex_destroy(&lock->base);
-}
-
-/**
- * ww_mutex_is_locked - is the w/w mutex locked
- * @lock: the mutex to be queried
- *
- * Returns 1 if the mutex is locked, 0 if unlocked.
- */
-static inline bool ww_mutex_is_locked(struct ww_mutex *lock)
-{
-	return mutex_is_locked(&lock->base);
-}
-
 extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
 
 #ifndef CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX