s390/locking: Use arch_try_cmpxchg() instead of __atomic_cmpxchg_bool()

Use arch_try_cmpxchg() instead of __atomic_cmpxchg_bool() everywhere.
This generates the same code like before, but uses the standard
cmpxchg() implementation instead of a custom __atomic_cmpxchg_bool().

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

2 files changed, 14 insertions, 11 deletions

diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 77d5e804af93..ac868a9bb0d1 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -57,8 +57,10 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lp)
 
 static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
 {
+	int old = 0;
+
 	barrier();
-	return likely(__atomic_cmpxchg_bool(&lp->lock, 0, SPINLOCK_LOCKVAL));
+	return likely(arch_try_cmpxchg(&lp->lock, &old, SPINLOCK_LOCKVAL));
 }
 
 static inline void arch_spin_lock(arch_spinlock_t *lp)
@@ -118,7 +120,9 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)
 
 static inline void arch_write_lock(arch_rwlock_t *rw)
 {
-	if (!__atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000))
+	int old = 0;
+
+	if (!arch_try_cmpxchg(&rw->cnts, &old, 0x30000))
 		arch_write_lock_wait(rw);
 }
 
@@ -133,8 +137,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 	int old;
 
 	old = READ_ONCE(rw->cnts);
-	return (!(old & 0xffff0000) &&
-		__atomic_cmpxchg_bool(&rw->cnts, old, old + 1));
+	return (!(old & 0xffff0000) && arch_try_cmpxchg(&rw->cnts, &old, old + 1));
 }
 
 static inline int arch_write_trylock(arch_rwlock_t *rw)
@@ -142,7 +145,7 @@ static inline int arch_write_trylock(arch_rwlock_t *rw)
 	int old;
 
 	old = READ_ONCE(rw->cnts);
-	return !old && __atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000);
+	return !old && arch_try_cmpxchg(&rw->cnts, &old, 0x30000);
 }
 
 #endif /* __ASM_SPINLOCK_H */
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 9f86ad8fa8b4..09d735010ee1 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -127,8 +127,8 @@ static inline void arch_spin_lock_queued(arch_spinlock_t *lp)
 	node_id = node->node_id;
 
 	/* Enqueue the node for this CPU in the spinlock wait queue */
+	old = READ_ONCE(lp->lock);
 	while (1) {
-		old = READ_ONCE(lp->lock);
 		if ((old & _Q_LOCK_CPU_MASK) == 0 &&
 		    (old & _Q_LOCK_STEAL_MASK) != _Q_LOCK_STEAL_MASK) {
 			/*
@@ -139,7 +139,7 @@ static inline void arch_spin_lock_queued(arch_spinlock_t *lp)
 			 * waiter will get the lock.
 			 */
 			new = (old ? (old + _Q_LOCK_STEAL_ADD) : 0) | lockval;
-			if (__atomic_cmpxchg_bool(&lp->lock, old, new))
+			if (arch_try_cmpxchg(&lp->lock, &old, new))
 				/* Got the lock */
 				goto out;
 			/* lock passing in progress */
@@ -147,7 +147,7 @@ static inline void arch_spin_lock_queued(arch_spinlock_t *lp)
 		}
 		/* Make the node of this CPU the new tail. */
 		new = node_id | (old & _Q_LOCK_MASK);
-		if (__atomic_cmpxchg_bool(&lp->lock, old, new))
+		if (arch_try_cmpxchg(&lp->lock, &old, new))
 			break;
 	}
 	/* Set the 'next' pointer of the tail node in the queue */
@@ -184,7 +184,7 @@ static inline void arch_spin_lock_queued(arch_spinlock_t *lp)
 		if (!owner) {
 			tail_id = old & _Q_TAIL_MASK;
 			new = ((tail_id != node_id) ? tail_id : 0) | lockval;
-			if (__atomic_cmpxchg_bool(&lp->lock, old, new))
+			if (arch_try_cmpxchg(&lp->lock, &old, new))
 				/* Got the lock */
 				break;
 			continue;
@@ -258,7 +258,7 @@ int arch_spin_trylock_retry(arch_spinlock_t *lp)
 		owner = READ_ONCE(lp->lock);
 		/* Try to get the lock if it is free. */
 		if (!owner) {
-			if (__atomic_cmpxchg_bool(&lp->lock, 0, cpu))
+			if (arch_try_cmpxchg(&lp->lock, &owner, cpu))
 				return 1;
 		}
 	}
@@ -300,7 +300,7 @@ void arch_write_lock_wait(arch_rwlock_t *rw)
 	while (1) {
 		old = READ_ONCE(rw->cnts);
 		if ((old & 0x1ffff) == 0 &&
-		    __atomic_cmpxchg_bool(&rw->cnts, old, old | 0x10000))
+		    arch_try_cmpxchg(&rw->cnts, &old, old | 0x10000))
 			/* Got the lock */
 			break;
 		barrier();