From c363b7ed79253d5b53494197f6ae625cff64694f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 15 Aug 2021 23:29:06 +0200 Subject: [PATCH] futex: Clean up stale comments The futex key reference mechanism is long gone. Clean up the stale comments which still mention it. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210815211305.249178312@linutronix.de --- kernel/futex.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index a1f27fd55a23..bc5395e66e97 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1354,7 +1354,7 @@ static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval) * - 1 - acquired the lock; * - <0 - error * - * The hb->lock and futex_key refs shall be held by the caller. + * The hb->lock must be held by the caller. * * @exiting is only set when the return value is -EBUSY. If so, this holds * a refcount on the exiting task on return and the caller needs to drop it @@ -2621,8 +2621,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q, * * Setup the futex_q and locate the hash_bucket. Get the futex value and * compare it with the expected value. Handle atomic faults internally. - * Return with the hb lock held and a q.key reference on success, and unlocked - * with no q.key reference on failure. + * Return with the hb lock held on success, and unlocked on failure. * * Return: * - 0 - uaddr contains val and hb has been locked; @@ -2700,8 +2699,8 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, current->timer_slack_ns); retry: /* - * Prepare to wait on uaddr. On success, holds hb lock and increments - * q.key refs. + * Prepare to wait on uaddr. On success, it holds hb->lock and q + * is initialized. */ ret = futex_wait_setup(uaddr, val, flags, &q, &hb); if (ret) @@ -2712,7 +2711,6 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, /* If we were woken (and unqueued), we succeeded, whatever. */ ret = 0; - /* unqueue_me() drops q.key ref */ if (!unqueue_me(&q)) goto out; ret = -ETIMEDOUT; @@ -3205,8 +3203,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, q.requeue_pi_key = &key2; /* - * Prepare to wait on uaddr. On success, increments q.key (key1) ref - * count. + * Prepare to wait on uaddr. On success, it holds hb->lock and q + * is initialized. */ ret = futex_wait_setup(uaddr, val, flags, &q, &hb); if (ret) @@ -3235,9 +3233,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, * In order for us to be here, we know our q.key == key2, and since * we took the hb->lock above, we also know that futex_requeue() has * completed and we no longer have to concern ourselves with a wakeup - * race with the atomic proxy lock acquisition by the requeue code. The - * futex_requeue dropped our key1 reference and incremented our key2 - * reference count. + * race with the atomic proxy lock acquisition by the requeue code. */ /*