Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d40d65c8 authored by Darren Hart's avatar Darren Hart Committed by Ingo Molnar
Browse files

futex: Correct queue_me and unqueue_me commentary 



The queue_me/unqueue_me commentary is oddly placed and out of date.
Clean it up and correct the inaccurate bits.

Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922053015.8717.71713.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 56ec1607

kernel/futex.c

+29 −12
Original line number Diff line number Diff line
@@ -1350,6 +1350,25 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q) 
	return hb;

}



static inline void

queue_unlock(struct futex_q *q, struct futex_hash_bucket *hb)

{

	spin_unlock(&hb->lock);

	drop_futex_key_refs(&q->key);

}



/**

 * queue_me() - Enqueue the futex_q on the futex_hash_bucket

 * @q:	The futex_q to enqueue

 * @hb:	The destination hash bucket

 *

 * The hb->lock must be held by the caller, and is released here. A call to

 * queue_me() is typically paired with exactly one call to unqueue_me().  The

 * exceptions involve the PI related operations, which may use unqueue_me_pi()

 * or nothing if the unqueue is done as part of the wake process and the unqueue

 * state is implicit in the state of woken task (see futex_wait_requeue_pi() for

 * an example).

 */

static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)

{

	int prio;
@@ -1373,19 +1392,17 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb) 
	spin_unlock(&hb->lock);

}



static inline void

queue_unlock(struct futex_q *q, struct futex_hash_bucket *hb)

{

	spin_unlock(&hb->lock);

	drop_futex_key_refs(&q->key);

}



/*

 * queue_me and unqueue_me must be called as a pair, each

 * exactly once.  They are called with the hashed spinlock held.

/**

 * unqueue_me() - Remove the futex_q from its futex_hash_bucket

 * @q:	The futex_q to unqueue

 *

 * The q->lock_ptr must not be held by the caller. A call to unqueue_me() must

 * be paired with exactly one earlier call to queue_me().

 *

 * Returns:

 *   1 - if the futex_q was still queued (and we removed unqueued it)

 *   0 - if the futex_q was already removed by the waking thread

 */



/* Return 1 if we were still queued (ie. 0 means we were woken) */

static int unqueue_me(struct futex_q *q)

{

	spinlock_t *lock_ptr;