s390/spinlock: use atomic primitives for spinlocks

Add a couple more __atomic_xxx function to atomic_ops.h and use them
to replace the compare-and-swap inlines in the spinlock code. This
changes the type of the lock value from unsigned int to int.

Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/atomic_ops.h

···
 
 static inline int __atomic_cmpxchg(int *ptr, int old, int new)
 {
-	asm volatile(
-		"	cs	%[old],%[new],%[ptr]"
-		: [old] "+d" (old), [ptr] "+Q" (*ptr)
-		: [new] "d" (new) : "cc", "memory");
-	return old;
+	return __sync_val_compare_and_swap(ptr, old, new);
+}
+
+static inline int __atomic_cmpxchg_bool(int *ptr, int old, int new)
+{
+	return __sync_bool_compare_and_swap(ptr, old, new);
 }
 
 static inline long __atomic64_cmpxchg(long *ptr, long old, long new)
 {
-	asm volatile(
-		"	csg	%[old],%[new],%[ptr]"
-		: [old] "+d" (old), [ptr] "+Q" (*ptr)
-		: [new] "d" (new) : "cc", "memory");
-	return old;
+	return __sync_val_compare_and_swap(ptr, old, new);
+}
+
+static inline long __atomic64_cmpxchg_bool(long *ptr, long old, long new)
+{
+	return __sync_bool_compare_and_swap(ptr, old, new);
 }
 
 #endif /* __ARCH_S390_ATOMIC_OPS__  */

arch/s390/include/asm/spinlock.h

···
 #define __ASM_SPINLOCK_H
 
 #include <linux/smp.h>
+#include <asm/atomic_ops.h>
 #include <asm/barrier.h>
 #include <asm/processor.h>
 
 #define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
 
 extern int spin_retry;
-
-static inline int
-_raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new)
-{
-	return __sync_bool_compare_and_swap(lock, old, new);
-}
 
 #ifndef CONFIG_SMP
 static inline bool arch_vcpu_is_preempted(int cpu) { return false; }
···
  * (the type definitions are in asm/spinlock_types.h)
  */
 
-void arch_lock_relax(unsigned int cpu);
+void arch_lock_relax(int cpu);
 
 void arch_spin_lock_wait(arch_spinlock_t *);
 int arch_spin_trylock_retry(arch_spinlock_t *);
···
 {
 	barrier();
 	return likely(arch_spin_value_unlocked(*lp) &&
-		      _raw_compare_and_swap(&lp->lock, 0, SPINLOCK_LOCKVAL));
+		      __atomic_cmpxchg_bool(&lp->lock, 0, SPINLOCK_LOCKVAL));
 }
 
 static inline void arch_spin_lock(arch_spinlock_t *lp)
···
 
 static inline void arch_spin_unlock(arch_spinlock_t *lp)
 {
-	typecheck(unsigned int, lp->lock);
+	typecheck(int, lp->lock);
 	asm volatile(
 		"st	%1,%0\n"
 		: "+Q" (lp->lock)
···
 
 static inline int arch_read_trylock_once(arch_rwlock_t *rw)
 {
-	unsigned int old = ACCESS_ONCE(rw->lock);
-	return likely((int) old >= 0 &&
-		      _raw_compare_and_swap(&rw->lock, old, old + 1));
+	int old = ACCESS_ONCE(rw->lock);
+	return likely(old >= 0 &&
+		      __atomic_cmpxchg_bool(&rw->lock, old, old + 1));
 }
 
 static inline int arch_write_trylock_once(arch_rwlock_t *rw)
 {
-	unsigned int old = ACCESS_ONCE(rw->lock);
+	int old = ACCESS_ONCE(rw->lock);
 	return likely(old == 0 &&
-		      _raw_compare_and_swap(&rw->lock, 0, 0x80000000));
+		      __atomic_cmpxchg_bool(&rw->lock, 0, 0x80000000));
 }
 
 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
···
 
 #define __RAW_LOCK(ptr, op_val, op_string)		\
 ({							\
-	unsigned int old_val;				\
+	int old_val;					\
 							\
-	typecheck(unsigned int *, ptr);			\
+	typecheck(int *, ptr);				\
 	asm volatile(					\
 		op_string "	%0,%2,%1\n"		\
 		"bcr	14,0\n"				\
···
 
 #define __RAW_UNLOCK(ptr, op_val, op_string)		\
 ({							\
-	unsigned int old_val;				\
+	int old_val;					\
 							\
-	typecheck(unsigned int *, ptr);			\
+	typecheck(int *, ptr);				\
 	asm volatile(					\
 		op_string "	%0,%2,%1\n"		\
 		: "=d" (old_val), "+Q" (*ptr)		\
···
 })
 
 extern void _raw_read_lock_wait(arch_rwlock_t *lp);
-extern void _raw_write_lock_wait(arch_rwlock_t *lp, unsigned int prev);
+extern void _raw_write_lock_wait(arch_rwlock_t *lp, int prev);
 
 static inline void arch_read_lock(arch_rwlock_t *rw)
 {
-	unsigned int old;
+	int old;
 
 	old = __RAW_LOCK(&rw->lock, 1, __RAW_OP_ADD);
-	if ((int) old < 0)
+	if (old < 0)
 		_raw_read_lock_wait(rw);
 }
 
···
 
 static inline void arch_write_lock(arch_rwlock_t *rw)
 {
-	unsigned int old;
+	int old;
 
 	old = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR);
 	if (old != 0)
···
 
 static inline void arch_read_unlock(arch_rwlock_t *rw)
 {
-	unsigned int old;
+	int old;
 
 	do {
 		old = ACCESS_ONCE(rw->lock);
-	} while (!_raw_compare_and_swap(&rw->lock, old, old - 1));
+	} while (!__atomic_cmpxchg_bool(&rw->lock, old, old - 1));
 }
 
 static inline void arch_write_lock(arch_rwlock_t *rw)
···
 
 static inline void arch_write_unlock(arch_rwlock_t *rw)
 {
-	typecheck(unsigned int, rw->lock);
+	typecheck(int, rw->lock);
 
 	rw->owner = 0;
 	asm volatile(

arch/s390/include/asm/spinlock_types.h

···
 #endif
 
 typedef struct {
-	unsigned int lock;
+	int lock;
 } __attribute__ ((aligned (4))) arch_spinlock_t;
 
 #define __ARCH_SPIN_LOCK_UNLOCKED { .lock = 0, }
 
 typedef struct {
-	unsigned int lock;
-	unsigned int owner;
+	int lock;
+	int owner;
 } arch_rwlock_t;
 
 #define __ARCH_RW_LOCK_UNLOCKED		{ 0 }

arch/s390/lib/spinlock.c

···
 }
 __setup("spin_retry=", spin_retry_setup);
 
-static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
+static inline void compare_and_delay(int *lock, int old)
 {
 	asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
 }
 
 void arch_spin_lock_wait(arch_spinlock_t *lp)
 {
-	unsigned int cpu = SPINLOCK_LOCKVAL;
-	unsigned int owner;
-	int count, first_diag;
+	int cpu = SPINLOCK_LOCKVAL;
+	int owner, count, first_diag;
 
 	first_diag = 1;
 	while (1) {
 		owner = ACCESS_ONCE(lp->lock);
 		/* Try to get the lock if it is free. */
 		if (!owner) {
-			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+			if (__atomic_cmpxchg_bool(&lp->lock, 0, cpu))
 				return;
 			continue;
 		}
···
 		count = spin_retry;
 		do {
 			if (MACHINE_HAS_CAD)
-				_raw_compare_and_delay(&lp->lock, owner);
+				compare_and_delay(&lp->lock, owner);
 			owner = ACCESS_ONCE(lp->lock);
 		} while (owner && count-- > 0);
 		if (!owner)
···
 
 void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
 {
-	unsigned int cpu = SPINLOCK_LOCKVAL;
-	unsigned int owner;
-	int count, first_diag;
+	int cpu = SPINLOCK_LOCKVAL;
+	int owner, count, first_diag;
 
 	local_irq_restore(flags);
 	first_diag = 1;
···
 		/* Try to get the lock if it is free. */
 		if (!owner) {
 			local_irq_disable();
-			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+			if (__atomic_cmpxchg_bool(&lp->lock, 0, cpu))
 				return;
 			local_irq_restore(flags);
 			continue;
···
 		count = spin_retry;
 		do {
 			if (MACHINE_HAS_CAD)
-				_raw_compare_and_delay(&lp->lock, owner);
+				compare_and_delay(&lp->lock, owner);
 			owner = ACCESS_ONCE(lp->lock);
 		} while (owner && count-- > 0);
 		if (!owner)
···
 
 int arch_spin_trylock_retry(arch_spinlock_t *lp)
 {
-	unsigned int cpu = SPINLOCK_LOCKVAL;
-	unsigned int owner;
-	int count;
+	int cpu = SPINLOCK_LOCKVAL;
+	int owner, count;
 
 	for (count = spin_retry; count > 0; count--) {
 		owner = READ_ONCE(lp->lock);
 		/* Try to get the lock if it is free. */
 		if (!owner) {
-			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+			if (__atomic_cmpxchg_bool(&lp->lock, 0, cpu))
 				return 1;
 		} else if (MACHINE_HAS_CAD)
-			_raw_compare_and_delay(&lp->lock, owner);
+			compare_and_delay(&lp->lock, owner);
 	}
 	return 0;
 }
···
 
 void _raw_read_lock_wait(arch_rwlock_t *rw)
 {
-	unsigned int owner, old;
 	int count = spin_retry;
+	int owner, old;
 
 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
 	__RAW_LOCK(&rw->lock, -1, __RAW_OP_ADD);
···
 		}
 		old = ACCESS_ONCE(rw->lock);
 		owner = ACCESS_ONCE(rw->owner);
-		if ((int) old < 0) {
+		if (old < 0) {
 			if (MACHINE_HAS_CAD)
-				_raw_compare_and_delay(&rw->lock, old);
+				compare_and_delay(&rw->lock, old);
 			continue;
 		}
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
+		if (__atomic_cmpxchg_bool(&rw->lock, old, old + 1))
 			return;
 	}
 }
···
 
 int _raw_read_trylock_retry(arch_rwlock_t *rw)
 {
-	unsigned int old;
 	int count = spin_retry;
+	int old;
 
 	while (count-- > 0) {
 		old = ACCESS_ONCE(rw->lock);
-		if ((int) old < 0) {
+		if (old < 0) {
 			if (MACHINE_HAS_CAD)
-				_raw_compare_and_delay(&rw->lock, old);
+				compare_and_delay(&rw->lock, old);
 			continue;
 		}
-		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
+		if (__atomic_cmpxchg_bool(&rw->lock, old, old + 1))
 			return 1;
 	}
 	return 0;
···
 
 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
 
-void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
+void _raw_write_lock_wait(arch_rwlock_t *rw, int prev)
 {
-	unsigned int owner, old;
 	int count = spin_retry;
+	int owner, old;
 
 	owner = 0;
 	while (1) {
···
 		old = ACCESS_ONCE(rw->lock);
 		owner = ACCESS_ONCE(rw->owner);
 		smp_mb();
-		if ((int) old >= 0) {
+		if (old >= 0) {
 			prev = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR);
 			old = prev;
 		}
-		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+		if ((old & 0x7fffffff) == 0 && prev >= 0)
 			break;
 		if (MACHINE_HAS_CAD)
-			_raw_compare_and_delay(&rw->lock, old);
+			compare_and_delay(&rw->lock, old);
 	}
 }
 EXPORT_SYMBOL(_raw_write_lock_wait);
···
 
 void _raw_write_lock_wait(arch_rwlock_t *rw)
 {
-	unsigned int owner, old, prev;
 	int count = spin_retry;
+	int owner, old, prev;
 
 	prev = 0x80000000;
 	owner = 0;
···
 		}
 		old = ACCESS_ONCE(rw->lock);
 		owner = ACCESS_ONCE(rw->owner);
-		if ((int) old >= 0 &&
-		    _raw_compare_and_swap(&rw->lock, old, old | 0x80000000))
+		if (old >= 0 &&
+		    __atomic_cmpxchg_bool(&rw->lock, old, old | 0x80000000))
 			prev = old;
 		else
 			smp_mb();
-		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+		if ((old & 0x7fffffff) == 0 && prev >= 0)
 			break;
 		if (MACHINE_HAS_CAD)
-			_raw_compare_and_delay(&rw->lock, old);
+			compare_and_delay(&rw->lock, old);
 	}
 }
 EXPORT_SYMBOL(_raw_write_lock_wait);
···
 
 int _raw_write_trylock_retry(arch_rwlock_t *rw)
 {
-	unsigned int old;
 	int count = spin_retry;
+	int old;
 
 	while (count-- > 0) {
 		old = ACCESS_ONCE(rw->lock);
 		if (old) {
 			if (MACHINE_HAS_CAD)
-				_raw_compare_and_delay(&rw->lock, old);
+				compare_and_delay(&rw->lock, old);
 			continue;
 		}
-		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
+		if (__atomic_cmpxchg_bool(&rw->lock, 0, 0x80000000))
 			return 1;
 	}
 	return 0;
 }
 EXPORT_SYMBOL(_raw_write_trylock_retry);
 
-void arch_lock_relax(unsigned int cpu)
+void arch_lock_relax(int cpu)
 {
 	if (!cpu)
 		return;