Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (4fa109b1) · Commits · e / devices / android_kernel_fairphone_FP5

include/linux/mutex.h

+0 −358

Original line number	Diff line number	Diff line
		@@ -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) \
		@@ -150,48 +113,12 @@ 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

include/linux/reservation.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -39,7 +39,7 @@
		#ifndef _LINUX_RESERVATION_H
		#define _LINUX_RESERVATION_H

		#include <linux/mutex.h>
		#include <linux/ww_mutex.h>

		extern struct ww_class reservation_ww_class;

include/linux/ww_mutex.h

0 → 100644

+378 −0

File added.

Preview size limit exceeded, changes collapsed.

kernel/mutex.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		* 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>

lib/locking-selftest.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,7 @@
		*/
		#include <linux/rwsem.h>
		#include <linux/mutex.h>
		#include <linux/ww_mutex.h>
		#include <linux/sched.h>
		#include <linux/delay.h>
		#include <linux/lockdep.h>