Commit 80681c04 authored by NeilBrown's avatar NeilBrown Committed by Peter Zijlstra
Browse files

sched: add wait_var_event_io() 



It is not currently possible to wait wait_var_event for an io_schedule()
style wait.  This patch adds wait_var_event_io() for that purpose.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240925053405.3960701-7-neilb@suse.de
parent cc2e1c82

include/linux/wait_bit.h

+31 −0
Original line number Diff line number Diff line
@@ -281,6 +281,9 @@ __out: __ret; \ 
#define __wait_var_event(var, condition)				\

	___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0,	\

			  schedule())

#define __wait_var_event_io(var, condition)				\

	___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0,	\

			  io_schedule())



/**

 * wait_var_event - wait for a variable to be updated and notified
@@ -306,6 +309,34 @@ do { \ 
	__wait_var_event(var, condition);				\

} while (0)



/**

 * wait_var_event_io - wait for a variable to be updated and notified

 * @var: the address of variable being waited on

 * @condition: the condition to wait for

 *

 * Wait for an IO related @condition to be true, only re-checking when a

 * wake up is received for the given @var (an arbitrary kernel address

 * which need not be directly related to the given condition, but

 * usually is).

 *

 * The process will wait on a waitqueue selected by hash from a shared

 * pool.  It will only be woken on a wake_up for the given address.

 *

 * This is similar to wait_var_event(), but calls io_schedule() instead

 * of schedule().

 *

 * The condition should normally use smp_load_acquire() or a similarly

 * ordered access to ensure that any changes to memory made before the

 * condition became true will be visible after the wait completes.

 */

#define wait_var_event_io(var, condition)				\

do {									\

	might_sleep();							\

	if (condition)							\

		break;							\

	__wait_var_event_io(var, condition);				\

} while (0)



#define __wait_var_event_killable(var, condition)			\

	___wait_var_event(var, condition, TASK_KILLABLE, 0, 0,		\

			  schedule())