Commit e52c4340 authored by Jens Axboe's avatar Jens Axboe
Browse files

futex: abstract out a __futex_wake_mark() helper 



Move the unqueue and lock_ptr clear into a helper that futex_wake_mark()
calls. Add it to the public functions as well, in preparation for using
it outside the core futex code.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 12a4be50

kernel/futex/futex.h

+1 −0
Original line number Diff line number Diff line
@@ -219,6 +219,7 @@ extern int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, 
			    struct futex_q *q, struct futex_hash_bucket **hb);

extern void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,

				   struct hrtimer_sleeper *timeout);

extern bool __futex_wake_mark(struct futex_q *q);

extern void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q);



extern int fault_in_user_writeable(u32 __user *uaddr);

kernel/futex/waitwake.c

+22 −11
Original line number Diff line number Diff line
@@ -106,20 +106,11 @@ 
 * double_lock_hb() and double_unlock_hb(), respectively.

 */



/*

 * The hash bucket lock must be held when this is called.

 * Afterwards, the futex_q must not be accessed. Callers

 * must ensure to later call wake_up_q() for the actual

 * wakeups to occur.

 */

void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)

bool __futex_wake_mark(struct futex_q *q)

{

	struct task_struct *p = q->task;



	if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n"))

		return;

		return false;



	get_task_struct(p);

	__futex_unqueue(q);

	/*

	 * The waiting task can free the futex_q as soon as q->lock_ptr = NULL
@@ -130,6 +121,26 @@ void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q) 
	 */

	smp_store_release(&q->lock_ptr, NULL);



	return true;

}



/*

 * The hash bucket lock must be held when this is called.

 * Afterwards, the futex_q must not be accessed. Callers

 * must ensure to later call wake_up_q() for the actual

 * wakeups to occur.

 */

void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)

{

	struct task_struct *p = q->task;



	get_task_struct(p);



	if (!__futex_wake_mark(q)) {

		put_task_struct(p);

		return;

	}



	/*

	 * Queue the task for later wakeup for after we've released

	 * the hb->lock.