locking/qspinlock: Improve readability

Restructure pv_queued_spin_steal_lock() as I found it hard to read.

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@hpe.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 8a99abf..429c3dc 100644 (file)
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -70,11 +70,14 @@ struct pv_node {
 static inline bool pv_queued_spin_steal_lock(struct qspinlock *lock)
 {
        struct __qspinlock *l = (void *)lock;
-       int ret = !(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) &&
-                  (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0);
 
-       qstat_inc(qstat_pv_lock_stealing, ret);
-       return ret;
+       if (!(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) &&
+           (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0)) {
+               qstat_inc(qstat_pv_lock_stealing, true);
+               return true;
+       }
+
+       return false;
 }
 
 /*
@@ -257,7 +260,6 @@ static struct pv_node *pv_unhash(struct qspinlock *lock)
 static inline bool
 pv_wait_early(struct pv_node *prev, int loop)
 {
-
        if ((loop & PV_PREV_CHECK_MASK) != 0)
                return false;