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>

diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index df19ae4..489a878 100644 (file)
--- 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;
        }