1 // SPDX-License-Identifier: GPL-2.0
3  * Generic wait-for-completion handler;
6  * wait_for_completion default blocks whereas semaphore default non-block. The
17  * complete: - signals a single thread waiting on this completion
32 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in complete()
34 	if (x->done != UINT_MAX)  in complete()
35 		x->done++;  in complete()
36 	swake_up_locked(&x->wait);  in complete()
37 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in complete()
42  * complete_all: - signals all threads waiting on this completion
63 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in complete_all()
64 	x->done = UINT_MAX;  in complete_all()
65 	swake_up_all_locked(&x->wait);  in complete_all()
66 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in complete_all()
74 	if (!x->done) {  in do_wait_for_common()
79 				timeout = -ERESTARTSYS;  in do_wait_for_common()
82 			__prepare_to_swait(&x->wait, &wait);  in do_wait_for_common()
84 			raw_spin_unlock_irq(&x->wait.lock);  in do_wait_for_common()
86 			raw_spin_lock_irq(&x->wait.lock);  in do_wait_for_common()
87 		} while (!x->done && timeout);  in do_wait_for_common()
88 		__finish_swait(&x->wait, &wait);  in do_wait_for_common()
89 		if (!x->done)  in do_wait_for_common()
92 	if (x->done != UINT_MAX)  in do_wait_for_common()
93 		x->done--;  in do_wait_for_common()
105 	raw_spin_lock_irq(&x->wait.lock);  in __wait_for_common()
107 	raw_spin_unlock_irq(&x->wait.lock);  in __wait_for_common()
127  * wait_for_completion: - waits for completion of a task
143  * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
162  * wait_for_completion_io: - waits for completion of a task
167  * for IO (which traditionally means blkio only).
176  * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
182  * interruptible. The caller is accounted as waiting for IO (which traditionally
196  * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
202  * Return: -ERESTARTSYS if interrupted, 0 if completed.
207 	if (t == -ERESTARTSYS)  in wait_for_completion_interruptible()
214  * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
221  * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
233  * wait_for_completion_killable: - waits for completion of a task (killable)
239  * Return: -ERESTARTSYS if interrupted, 0 if completed.
244 	if (t == -ERESTARTSYS)  in wait_for_completion_killable()
251  * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
259  * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
271  *	try_wait_for_completion - try to decrement a completion without blocking
274  *	Return: 0 if a decrement cannot be done without blocking
278  *	attempt to decrement the counter without blocking. This
288 	 * Since x->done will need to be locked only  in try_wait_for_completion()
289 	 * in the non-blocking case, we check x->done  in try_wait_for_completion()
291 	 * return early in the blocking case.  in try_wait_for_completion()
293 	if (!READ_ONCE(x->done))  in try_wait_for_completion()
296 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in try_wait_for_completion()
297 	if (!x->done)  in try_wait_for_completion()
299 	else if (x->done != UINT_MAX)  in try_wait_for_completion()
300 		x->done--;  in try_wait_for_completion()
301 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in try_wait_for_completion()
307  *	completion_done - Test to see if a completion has any waiters
319 	if (!READ_ONCE(x->done))  in completion_done()
323 	 * If ->done, we need to wait for complete() to release ->wait.lock  in completion_done()
327 	raw_spin_lock_irqsave(&x->wait.lock, flags);  in completion_done()
328 	raw_spin_unlock_irqrestore(&x->wait.lock, flags);  in completion_done()