1 // SPDX-License-Identifier: GPL-2.0
4  * Generic wait-for-completion handler;
7  * wait_for_completion default blocks whereas semaphore default non-block. The
20 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in complete_with_flags()
22 	if (x->done != UINT_MAX)  in complete_with_flags()
23 		x->done++;  in complete_with_flags()
24 	swake_up_locked(&x->wait, wake_flags);  in complete_with_flags()
25 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in complete_with_flags()
34  * complete: - signals a single thread waiting on this completion
52  * complete_all: - signals all threads waiting on this completion
73 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in complete_all()
74 	x->done = UINT_MAX;  in complete_all()
75 	swake_up_all_locked(&x->wait);  in complete_all()
76 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in complete_all()
84 	if (!x->done) {  in do_wait_for_common()
89 				timeout = -ERESTARTSYS;  in do_wait_for_common()
92 			__prepare_to_swait(&x->wait, &wait);  in do_wait_for_common()
94 			raw_spin_unlock_irq(&x->wait.lock);  in do_wait_for_common()
96 			raw_spin_lock_irq(&x->wait.lock);  in do_wait_for_common()
97 		} while (!x->done && timeout);  in do_wait_for_common()
98 		__finish_swait(&x->wait, &wait);  in do_wait_for_common()
99 		if (!x->done)  in do_wait_for_common()
102 	if (x->done != UINT_MAX)  in do_wait_for_common()
103 		x->done--;  in do_wait_for_common()
115 	raw_spin_lock_irq(&x->wait.lock);  in __wait_for_common()
117 	raw_spin_unlock_irq(&x->wait.lock);  in __wait_for_common()
137  * wait_for_completion: - waits for completion of a task
153  * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
172  * wait_for_completion_io: - waits for completion of a task
177  * for IO (which traditionally means blkio only).
186  * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
192  * interruptible. The caller is accounted as waiting for IO (which traditionally
206  * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
212  * Return: -ERESTARTSYS if interrupted, 0 if completed.
218 	if (t == -ERESTARTSYS)  in wait_for_completion_interruptible()
225  * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
232  * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
244  * wait_for_completion_killable: - waits for completion of a task (killable)
250  * Return: -ERESTARTSYS if interrupted, 0 if completed.
256 	if (t == -ERESTARTSYS)  in wait_for_completion_killable()
266 	if (t == -ERESTARTSYS)  in wait_for_completion_state()
273  * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
281  * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
293  *	try_wait_for_completion - try to decrement a completion without blocking
296  *	Return: 0 if a decrement cannot be done without blocking
300  *	attempt to decrement the counter without blocking. This
310 	 * Since x->done will need to be locked only  in try_wait_for_completion()
311 	 * in the non-blocking case, we check x->done  in try_wait_for_completion()
313 	 * return early in the blocking case.  in try_wait_for_completion()
315 	if (!READ_ONCE(x->done))  in try_wait_for_completion()
318 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in try_wait_for_completion()
319 	if (!x->done)  in try_wait_for_completion()
321 	else if (x->done != UINT_MAX)  in try_wait_for_completion()
322 		x->done--;  in try_wait_for_completion()
323 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in try_wait_for_completion()
329  *	completion_done - Test to see if a completion has any waiters
341 	if (!READ_ONCE(x->done))  in completion_done()
345 	 * If ->done, we need to wait for complete() to release ->wait.lock  in completion_done()
349 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in completion_done()
350 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in completion_done()