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futex: Simplify handle_early_requeue_pi_wakeup()

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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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.638938670@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-08-15 23:29:17 +02:00 committed by Ingo Molnar
parent d69cba5c71
commit 6231acbd08
1 changed files with 22 additions and 26 deletions
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48
kernel/futex.c
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@ -3070,27 +3070,22 @@ pi_faulted:
}
/**
* 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.
@ -3099,22 +3094,21 @@ 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));
/*
* We were woken prior to requeue by a timeout or a signal.
* Unqueue the futex_q and determine which it was.
*/
plist_del(&q->list, &hb->chain);
hb_waiters_dec(hb);
WARN_ON_ONCE(&hb->lock != q->lock_ptr);
/* Handle spurious wakeups gracefully */
ret = -EWOULDBLOCK;
if (timeout && !timeout->task)
ret = -ETIMEDOUT;
else if (signal_pending(current))
ret = -ERESTARTNOINTR;
}
/*
* We were woken prior to requeue by a timeout or a signal.
* Unqueue the futex_q and determine which it was.
*/
plist_del(&q->list, &hb->chain);
hb_waiters_dec(hb);
/* Handle spurious wakeups gracefully */
ret = -EWOULDBLOCK;
if (timeout && !timeout->task)
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;