1 /* SPDX-License-Identifier: GPL-2.0 */
9  * Wait/Die implementation:
35 #define ww_mutex_base_is_locked(b)	rt_mutex_base_is_locked(&(b)->rtmutex)
98  * ww_mutex_init - initialize the w/w mutex
111 	ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);  in ww_mutex_init()
112 	lock->ctx = NULL;  in ww_mutex_init()
114 	lock->ww_class = ww_class;  in ww_mutex_init()
119  * ww_acquire_init - initialize a w/w acquire context
125  * Context-based w/w mutex acquiring can be done in any order whatsoever within
127  * wait/die logic.
129  * Mixing of context-based w/w mutex acquiring and single w/w mutex locking can
140  * on the stack.
145 	ctx->task = current;  in ww_acquire_init()
146 	ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);  in ww_acquire_init()
147 	ctx->acquired = 0;  in ww_acquire_init()
148 	ctx->wounded = false;  in ww_acquire_init()
149 	ctx->is_wait_die = ww_class->is_wait_die;  in ww_acquire_init()
151 	ctx->ww_class = ww_class;  in ww_acquire_init()
152 	ctx->done_acquire = 0;  in ww_acquire_init()
153 	ctx->contending_lock = NULL;  in ww_acquire_init()
157 	lockdep_init_map(&ctx->dep_map, ww_class->acquire_name,  in ww_acquire_init()
158 			 &ww_class->acquire_key, 0);  in ww_acquire_init()
159 	lockdep_init_map_wait(&ctx->first_lock_dep_map, ww_class->mutex_name,  in ww_acquire_init()
160 			      &ww_class->mutex_key, 0, LD_WAIT_SLEEP);  in ww_acquire_init()
161 	mutex_acquire(&ctx->dep_map, 0, 0, _RET_IP_);  in ww_acquire_init()
162 	mutex_acquire_nest(&ctx->first_lock_dep_map, 0, 0, &ctx->dep_map, _RET_IP_);  in ww_acquire_init()
165 	ctx->deadlock_inject_interval = 1;  in ww_acquire_init()
166 	ctx->deadlock_inject_countdown = ctx->stamp & 0xf;  in ww_acquire_init()
171  * ww_acquire_done - marks the end of the acquire phase
186 	DEBUG_LOCKS_WARN_ON(ctx->done_acquire);  in ww_acquire_done()
187 	ctx->done_acquire = 1;  in ww_acquire_done()
192  * ww_acquire_fini - releases a w/w acquire context
201 	mutex_release(&ctx->first_lock_dep_map, _THIS_IP_);  in ww_acquire_fini()
202 	mutex_release(&ctx->dep_map, _THIS_IP_);  in ww_acquire_fini()
205 	DEBUG_LOCKS_WARN_ON(ctx->acquired);  in ww_acquire_fini()
211 		ctx->done_acquire = 1;  in ww_acquire_fini()
215 		ctx->acquired = ~0U;  in ww_acquire_fini()
220  * ww_mutex_lock - acquire the w/w mutex
227  * wait/die algorithm. If the lock isn't immediately available this function
229  * for backing off by returning -EDEADLK (die case). Trying to acquire the
231  * returning -EALREADY. Returns 0 if the mutex was successfully acquired.
233  * In the die case the caller must release all currently held w/w mutexes for
239  * The mutex must later on be released by the same task that
243  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
251  * ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
258  * wait/die algorithm. If the lock isn't immediately available this function
260  * for backing off by returning -EDEADLK (die case). Trying to acquire the
262  * returning -EALREADY. Returns 0 if the mutex was successfully acquired. If a
263  * signal arrives while waiting for the lock then this function returns -EINTR.
265  * In the die case the caller must release all currently held w/w mutexes for
271  * The mutex must later on be released by the same task that
275  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
284  * ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
288  * Acquires a w/w mutex with the given context after a die case. This function
292  * context and then call this function on the contended lock.
295  * needs with ww_mutex_lock. Note that the -EALREADY return code from
299  * with the context held. It is forbidden to call this on anything else than the
311 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow()
318  * ww_mutex_lock_slow_interruptible - slowpath acquiring of the w/w mutex, interruptible
322  * Acquires a w/w mutex with the given context after a die case. This function
325  * function returns -EINTR.
328  * context and then call this function on the contended lock.
331  * needs with ww_mutex_lock. Note that the -EALREADY return code from
335  * with the given context held. It is forbidden to call this on anything else
347 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow_interruptible()
358  * ww_mutex_destroy - mark a w/w mutex unusable
368 	mutex_destroy(&lock->base);  in ww_mutex_destroy()
373  * ww_mutex_is_locked - is the w/w mutex locked
380 	return ww_mutex_base_is_locked(&lock->base);  in ww_mutex_is_locked()