1 /* SPDX-License-Identifier: GPL-2.0 */
9  * Wait/Die implementation:
37 #define ww_mutex_base_is_locked(b)	rt_mutex_base_is_locked(&(b)->rtmutex)
90  * ww_mutex_init - initialize the w/w mutex
103 	ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);  in ww_mutex_init()
104 	lock->ctx = NULL;  in ww_mutex_init()
106 	lock->ww_class = ww_class;  in ww_mutex_init()
111  * ww_acquire_init - initialize a w/w acquire context
117  * Context-based w/w mutex acquiring can be done in any order whatsoever within
119  * wait/die logic.
121  * Mixing of context-based w/w mutex acquiring and single w/w mutex locking can
132  * on the stack.
137 	ctx->task = current;  in ww_acquire_init()
138 	ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);  in ww_acquire_init()
139 	ctx->acquired = 0;  in ww_acquire_init()
140 	ctx->wounded = false;  in ww_acquire_init()
141 	ctx->is_wait_die = ww_class->is_wait_die;  in ww_acquire_init()
143 	ctx->ww_class = ww_class;  in ww_acquire_init()
144 	ctx->done_acquire = 0;  in ww_acquire_init()
145 	ctx->contending_lock = NULL;  in ww_acquire_init()
149 	lockdep_init_map(&ctx->dep_map, ww_class->acquire_name,  in ww_acquire_init()
150 			 &ww_class->acquire_key, 0);  in ww_acquire_init()
151 	mutex_acquire(&ctx->dep_map, 0, 0, _RET_IP_);  in ww_acquire_init()
154 	ctx->deadlock_inject_interval = 1;  in ww_acquire_init()
155 	ctx->deadlock_inject_countdown = ctx->stamp & 0xf;  in ww_acquire_init()
160  * ww_acquire_done - marks the end of the acquire phase
175 	DEBUG_LOCKS_WARN_ON(ctx->done_acquire);  in ww_acquire_done()
176 	ctx->done_acquire = 1;  in ww_acquire_done()
181  * ww_acquire_fini - releases a w/w acquire context
190 	mutex_release(&ctx->dep_map, _THIS_IP_);  in ww_acquire_fini()
193 	DEBUG_LOCKS_WARN_ON(ctx->acquired);  in ww_acquire_fini()
199 		ctx->done_acquire = 1;  in ww_acquire_fini()
203 		ctx->acquired = ~0U;  in ww_acquire_fini()
208  * ww_mutex_lock - acquire the w/w mutex
215  * wait/die algorithm. If the lock isn't immediately available this function
217  * for backing off by returning -EDEADLK (die case). Trying to acquire the
219  * returning -EALREADY. Returns 0 if the mutex was successfully acquired.
221  * In the die case the caller must release all currently held w/w mutexes for
227  * The mutex must later on be released by the same task that
231  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
239  * ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
246  * wait/die algorithm. If the lock isn't immediately available this function
248  * for backing off by returning -EDEADLK (die case). Trying to acquire the
250  * returning -EALREADY. Returns 0 if the mutex was successfully acquired. If a
251  * signal arrives while waiting for the lock then this function returns -EINTR.
253  * In the die case the caller must release all currently held w/w mutexes for
259  * The mutex must later on be released by the same task that
263  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
272  * ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
276  * Acquires a w/w mutex with the given context after a die case. This function
280  * context and then call this function on the contended lock.
283  * needs with ww_mutex_lock. Note that the -EALREADY return code from
287  * with the context held. It is forbidden to call this on anything else than the
299 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow()
306  * ww_mutex_lock_slow_interruptible - slowpath acquiring of the w/w mutex, interruptible
310  * Acquires a w/w mutex with the given context after a die case. This function
313  * function returns -EINTR.
316  * context and then call this function on the contended lock.
319  * needs with ww_mutex_lock. Note that the -EALREADY return code from
323  * with the given context held. It is forbidden to call this on anything else
335 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow_interruptible()
343  * ww_mutex_trylock - tries to acquire the w/w mutex without acquire context
351 	return ww_mutex_base_trylock(&lock->base);  in ww_mutex_trylock()
355  * ww_mutex_destroy - mark a w/w mutex unusable
365 	mutex_destroy(&lock->base);  in ww_mutex_destroy()
370  * ww_mutex_is_locked - is the w/w mutex locked
377 	return ww_mutex_base_is_locked(&lock->base);  in ww_mutex_is_locked()