1 /* SPDX-License-Identifier: GPL-2.0 */
9  * Wait/Die implementation:
86  * ww_mutex_init - initialize the w/w mutex
98 	__mutex_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);  in ww_mutex_init()
99 	lock->ctx = NULL;  in ww_mutex_init()
101 	lock->ww_class = ww_class;  in ww_mutex_init()
106  * ww_acquire_init - initialize a w/w acquire context
112  * Context-based w/w mutex acquiring can be done in any order whatsoever within
114  * wait/die logic.
116  * Mixing of context-based w/w mutex acquiring and single w/w mutex locking can
127  * on the stack.
132 	ctx->task = current;  in ww_acquire_init()
133 	ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);  in ww_acquire_init()
134 	ctx->acquired = 0;  in ww_acquire_init()
135 	ctx->wounded = false;  in ww_acquire_init()
136 	ctx->is_wait_die = ww_class->is_wait_die;  in ww_acquire_init()
138 	ctx->ww_class = ww_class;  in ww_acquire_init()
139 	ctx->done_acquire = 0;  in ww_acquire_init()
140 	ctx->contending_lock = NULL;  in ww_acquire_init()
144 	lockdep_init_map(&ctx->dep_map, ww_class->acquire_name,  in ww_acquire_init()
145 			 &ww_class->acquire_key, 0);  in ww_acquire_init()
146 	mutex_acquire(&ctx->dep_map, 0, 0, _RET_IP_);  in ww_acquire_init()
149 	ctx->deadlock_inject_interval = 1;  in ww_acquire_init()
150 	ctx->deadlock_inject_countdown = ctx->stamp & 0xf;  in ww_acquire_init()
155  * ww_acquire_done - marks the end of the acquire phase
170 	DEBUG_LOCKS_WARN_ON(ctx->done_acquire);  in ww_acquire_done()
171 	ctx->done_acquire = 1;  in ww_acquire_done()
176  * ww_acquire_fini - releases a w/w acquire context
185 	mutex_release(&ctx->dep_map, 0, _THIS_IP_);  in ww_acquire_fini()
187 	DEBUG_LOCKS_WARN_ON(ctx->acquired);  in ww_acquire_fini()
193 		ctx->done_acquire = 1;  in ww_acquire_fini()
197 		ctx->acquired = ~0U;  in ww_acquire_fini()
202  * ww_mutex_lock - acquire the w/w mutex
209  * wait/die algorithm. If the lock isn't immediately available this function
211  * for backing off by returning -EDEADLK (die case). Trying to acquire the
213  * returning -EALREADY. Returns 0 if the mutex was successfully acquired.
215  * In the die case the caller must release all currently held w/w mutexes for
221  * The mutex must later on be released by the same task that
225  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
233  * ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
240  * wait/die algorithm. If the lock isn't immediately available this function
242  * for backing off by returning -EDEADLK (die case). Trying to acquire the
244  * returning -EALREADY. Returns 0 if the mutex was successfully acquired. If a
245  * signal arrives while waiting for the lock then this function returns -EINTR.
247  * In the die case the caller must release all currently held w/w mutexes for
253  * The mutex must later on be released by the same task that
257  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
266  * ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
270  * Acquires a w/w mutex with the given context after a die case. This function
274  * context and then call this function on the contended lock.
277  * needs with ww_mutex_lock. Note that the -EALREADY return code from
281  * with the context held. It is forbidden to call this on anything else than the
293 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow()
300  * ww_mutex_lock_slow_interruptible - slowpath acquiring of the w/w mutex, interruptible
304  * Acquires a w/w mutex with the given context after a die case. This function
307  * function returns -EINTR.
310  * context and then call this function on the contended lock.
313  * needs with ww_mutex_lock. Note that the -EALREADY return code from
317  * with the given context held. It is forbidden to call this on anything else
329 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow_interruptible()
337  * ww_mutex_trylock - tries to acquire the w/w mutex without acquire context
345 	return mutex_trylock(&lock->base);  in ww_mutex_trylock()
349  * ww_mutex_destroy - mark a w/w mutex unusable
358 	mutex_destroy(&lock->base);  in ww_mutex_destroy()
362  * ww_mutex_is_locked - is the w/w mutex locked
369 	return mutex_is_locked(&lock->base);  in ww_mutex_is_locked()