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futex: Correct queue_me and unqueue_me commentary

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The queue_me/unqueue_me commentary is oddly placed and out of date.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

Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter 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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Darren Hart 2009-09-21 22:30:15 -07:00 committed by Ingo Molnar
parent 56ec1607b1
commit d40d65c8db
1 changed files with 29 additions and 12 deletions
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41
kernel/futex.c
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@ -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;