The following commit has been merged into the locking/core branch of tip:

Commit-ID:     a3f2428d2b9c9ca70f52818774a2f6e0e30a0f0b
Gitweb:        
https://git.kernel.org/tip/a3f2428d2b9c9ca70f52818774a2f6e0e30a0f0b
Author:        Davidlohr Bueso <d...@stgolabs.net>
AuthorDate:    Fri, 26 Feb 2021 09:50:28 -08:00
Committer:     Thomas Gleixner <t...@linutronix.de>
CommitterDate: Thu, 11 Mar 2021 19:19:17 +01:00

kernel/futex: Move hb unlock out of unqueue_me_pi()

This improves the code readability, and the locking more obvious
as it becomes symmetric for the caller.

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Link: https://lore.kernel.org/r/20210226175029.50335-3-d...@stgolabs.net

---
 kernel/futex.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index ee09995..dcd6132 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2318,19 +2318,15 @@ retry:
 
 /*
  * PI futexes can not be requeued and must remove themself from the
- * hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry
- * and dropped here.
+ * hash bucket. The hash bucket lock (i.e. lock_ptr) is held.
  */
 static void unqueue_me_pi(struct futex_q *q)
-       __releases(q->lock_ptr)
 {
        __unqueue_futex(q);
 
        BUG_ON(!q->pi_state);
        put_pi_state(q->pi_state);
        q->pi_state = NULL;
-
-       spin_unlock(q->lock_ptr);
 }
 
 static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
@@ -2913,8 +2909,8 @@ no_block:
        if (res)
                ret = (res < 0) ? res : 0;
 
-       /* Unqueue and drop the lock */
        unqueue_me_pi(&q);
+       spin_unlock(q.lock_ptr);
        goto out;
 
 out_unlock_put_key:
@@ -3290,8 +3286,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, 
unsigned int flags,
                if (res)
                        ret = (res < 0) ? res : 0;
 
-               /* Unqueue and drop the lock. */
                unqueue_me_pi(&q);
+               spin_unlock(q.lock_ptr);
        }
 
        if (ret == -EINTR) {

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