The following commit has been merged into the locking/core branch of tip: Commit-ID: 6231acbd0802e76580c71ceb52c09646d42170fb Gitweb: https://git.kernel.org/tip/6231acbd0802e76580c71ceb52c09646d42170fb Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Sun, 15 Aug 2021 23:29:17 +02:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 17 Aug 2021 19:05:57 +02:00 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: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210815211305.638938670@xxxxxxxxxxxxx --- kernel/futex.c | 48 ++++++++++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 26 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index a5232f6..82660b9 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -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;
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