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Commit 82e06c81 authored by Shaohua Li's avatar Shaohua Li Committed by NeilBrown
Browse files

wait: add wait_event_cmd() 



Add a new API wait_event_cmd(). It's a variant of wait_even() with two
commands executed. One is executed before sleep, another after sleep.

Modified to match use wait.h approach based on suggestion by
Peter Zijlstra <peterz@infradead.org> - neilb

Signed-off-by: default avatarShaohua Li <shli@fusionio.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent ba8805b9

include/linux/wait.h

+25 −0
Original line number Diff line number Diff line
@@ -278,6 +278,31 @@ do { \ 
	__ret;								\

})



#define __wait_event_cmd(wq, condition, cmd1, cmd2)			\

	(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,	\

			    cmd1; schedule(); cmd2)



/**

 * wait_event_cmd - sleep until a condition gets true

 * @wq: the waitqueue to wait on

 * @condition: a C expression for the event to wait for

 * cmd1: the command will be executed before sleep

 * cmd2: the command will be executed after sleep

 *

 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the

 * @condition evaluates to true. The @condition is checked each time

 * the waitqueue @wq is woken up.

 *

 * wake_up() has to be called after changing any variable that could

 * change the result of the wait condition.

 */

#define wait_event_cmd(wq, condition, cmd1, cmd2)			\

do {									\

	if (condition)							\

		break;							\

	__wait_event_cmd(wq, condition, cmd1, cmd2);			\

} while (0)



#define __wait_event_interruptible(wq, condition)			\

	___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,		\

		      schedule())