1 /* SPDX-License-Identifier: GPL-2.0 */
9  * Wait/Die implementation:
78  * ww_mutex_init - initialize the w/w mutex
90 	__mutex_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);  in ww_mutex_init()
91 	lock->ctx = NULL;  in ww_mutex_init()
93 	lock->ww_class = ww_class;  in ww_mutex_init()
98  * ww_acquire_init - initialize a w/w acquire context
104  * Context-based w/w mutex acquiring can be done in any order whatsoever within
106  * wait/die logic.
108  * Mixing of context-based w/w mutex acquiring and single w/w mutex locking can
119  * on the stack.
124 	ctx->task = current;  in ww_acquire_init()
125 	ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);  in ww_acquire_init()
126 	ctx->acquired = 0;  in ww_acquire_init()
127 	ctx->wounded = false;  in ww_acquire_init()
128 	ctx->is_wait_die = ww_class->is_wait_die;  in ww_acquire_init()
130 	ctx->ww_class = ww_class;  in ww_acquire_init()
131 	ctx->done_acquire = 0;  in ww_acquire_init()
132 	ctx->contending_lock = NULL;  in ww_acquire_init()
136 	lockdep_init_map(&ctx->dep_map, ww_class->acquire_name,  in ww_acquire_init()
137 			 &ww_class->acquire_key, 0);  in ww_acquire_init()
138 	mutex_acquire(&ctx->dep_map, 0, 0, _RET_IP_);  in ww_acquire_init()
141 	ctx->deadlock_inject_interval = 1;  in ww_acquire_init()
142 	ctx->deadlock_inject_countdown = ctx->stamp & 0xf;  in ww_acquire_init()
147  * ww_acquire_done - marks the end of the acquire phase
162 	DEBUG_LOCKS_WARN_ON(ctx->done_acquire);  in ww_acquire_done()
163 	ctx->done_acquire = 1;  in ww_acquire_done()
168  * ww_acquire_fini - releases a w/w acquire context
177 	mutex_release(&ctx->dep_map, _THIS_IP_);  in ww_acquire_fini()
179 	DEBUG_LOCKS_WARN_ON(ctx->acquired);  in ww_acquire_fini()
185 		ctx->done_acquire = 1;  in ww_acquire_fini()
189 		ctx->acquired = ~0U;  in ww_acquire_fini()
194  * ww_mutex_lock - acquire the w/w mutex
201  * wait/die algorithm. If the lock isn't immediately available this function
203  * for backing off by returning -EDEADLK (die case). Trying to acquire the
205  * returning -EALREADY. Returns 0 if the mutex was successfully acquired.
207  * In the die case the caller must release all currently held w/w mutexes for
213  * The mutex must later on be released by the same task that
217  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
225  * ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
232  * wait/die algorithm. If the lock isn't immediately available this function
234  * for backing off by returning -EDEADLK (die case). Trying to acquire the
236  * returning -EALREADY. Returns 0 if the mutex was successfully acquired. If a
237  * signal arrives while waiting for the lock then this function returns -EINTR.
239  * In the die case the caller must release all currently held w/w mutexes for
245  * The mutex must later on be released by the same task that
249  * can be locked. memset()-ing the mutex to 0 is not allowed. The mutex must be
258  * ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
262  * Acquires a w/w mutex with the given context after a die case. This function
266  * context and then call this function on the contended lock.
269  * needs with ww_mutex_lock. Note that the -EALREADY return code from
273  * with the context held. It is forbidden to call this on anything else than the
285 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow()
292  * ww_mutex_lock_slow_interruptible - slowpath acquiring of the w/w mutex, interruptible
296  * Acquires a w/w mutex with the given context after a die case. This function
299  * function returns -EINTR.
302  * context and then call this function on the contended lock.
305  * needs with ww_mutex_lock. Note that the -EALREADY return code from
309  * with the given context held. It is forbidden to call this on anything else
321 	DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);  in ww_mutex_lock_slow_interruptible()
329  * ww_mutex_trylock - tries to acquire the w/w mutex without acquire context
337 	return mutex_trylock(&lock->base);  in ww_mutex_trylock()
341  * ww_mutex_destroy - mark a w/w mutex unusable
350 	mutex_destroy(&lock->base);  in ww_mutex_destroy()
354  * ww_mutex_is_locked - is the w/w mutex locked
361 	return mutex_is_locked(&lock->base);  in ww_mutex_is_locked()