locking: Clean up pvqspinlock warning

 - Rename the on-stack variable to match the datastructure variable,

 - place the cmpxchg back under the comment that explains it,

 - clean up the WARN() statement to avoid superfluous conditionals
   and line-breaks.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index df19ae4debd0..489a87884337 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -287,20 +287,21 @@ __visible void __pv_queued_spin_unlock(struct qspinlock *lock)
 {
         struct __qspinlock *l = (void *)lock;
         struct pv_node *node;
-        u8 lockval = cmpxchg(&l->locked, _Q_LOCKED_VAL, 0);
+        u8 locked;
 
         /*
          * We must not unlock if SLOW, because in that case we must first
          * unhash. Otherwise it would be possible to have multiple @lock
          * entries, which would be BAD.
          */
-        if (likely(lockval == _Q_LOCKED_VAL))
+        locked = cmpxchg(&l->locked, _Q_LOCKED_VAL, 0);
+        if (likely(locked == _Q_LOCKED_VAL))
                 return;
 
-        if (unlikely(lockval != _Q_SLOW_VAL)) {
-                if (debug_locks_silent)
-                        return;
-                WARN(1, "pvqspinlock: lock %p has corrupted value 0x%x!\n", lock, atomic_read(&lock->val));
+        if (unlikely(locked != _Q_SLOW_VAL)) {
+                WARN(!debug_locks_silent,
+                     "pvqspinlock: lock 0x%lx has corrupted value 0x%x!\n",
+                     (unsigned long)lock, atomic_read(&lock->val));
                 return;
         }