Commit 6231acbd authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

futex: Simplify handle_early_requeue_pi_wakeup() 



Move the futex key match out of handle_early_requeue_pi_wakeup() which
allows to simplify that function. The upcoming state machine for
requeue_pi() will make that go away.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.638938670@linutronix.de
parent d69cba5c

kernel/futex.c

+22 −26
Original line number Diff line number Diff line
@@ -3070,27 +3070,22 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) 
}



/**

 * handle_early_requeue_pi_wakeup() - Detect early wakeup on the initial futex

 * handle_early_requeue_pi_wakeup() - Handle early wakeup on the initial futex

 * @hb:		the hash_bucket futex_q was original enqueued on

 * @q:		the futex_q woken while waiting to be requeued

 * @key2:	the futex_key of the requeue target futex

 * @timeout:	the timeout associated with the wait (NULL if none)

 *

 * Detect if the task was woken on the initial futex as opposed to the requeue

 * target futex.  If so, determine if it was a timeout or a signal that caused

 * the wakeup and return the appropriate error code to the caller.  Must be

 * called with the hb lock held.

 * Determine the cause for the early wakeup.

 *

 * Return:

 *  -  0 = no early wakeup detected;

 *  - <0 = -ETIMEDOUT or -ERESTARTNOINTR

 *  -EWOULDBLOCK or -ETIMEDOUT or -ERESTARTNOINTR

 */

static inline

int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,

				   struct futex_q *q, union futex_key *key2,

				   struct futex_q *q,

				   struct hrtimer_sleeper *timeout)

{

	int ret = 0;

	int ret;



	/*

	 * With the hb lock held, we avoid races while we process the wakeup.
@@ -3099,8 +3094,8 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, 
	 * It can't be requeued from uaddr2 to something else since we don't

	 * support a PI aware source futex for requeue.

	 */

	if (!match_futex(&q->key, key2)) {

		WARN_ON(q->lock_ptr && (&hb->lock != q->lock_ptr));

	WARN_ON_ONCE(&hb->lock != q->lock_ptr);



	/*

	 * We were woken prior to requeue by a timeout or a signal.

	 * Unqueue the futex_q and determine which it was.
@@ -3114,7 +3109,6 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, 
		ret = -ETIMEDOUT;

	else if (signal_pending(current))

		ret = -ERESTARTNOINTR;

	}

	return ret;

}
@@ -3217,7 +3211,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, 
	futex_wait_queue_me(hb, &q, to);



	spin_lock(&hb->lock);

	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);

	/* Is @q still queued on uaddr1? */

	if (!match_futex(&q->key, key2))

		ret = handle_early_requeue_pi_wakeup(hb, &q, to);

	spin_unlock(&hb->lock);

	if (ret)

		goto out;