From 02c503ff237cdcd8e012a122a638295550db10a5 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 28 Nov 2016 15:50:48 +0100
Subject: [PATCH] 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 <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/atomic_ops.h | 22 ++++----
arch/s390/include/asm/spinlock.h | 45 +++++++---------
arch/s390/include/asm/spinlock_types.h | 6 +--
arch/s390/lib/spinlock.c | 73 ++++++++++++--------------
4 files changed, 70 insertions(+), 76 deletions(-)
diff --git a/arch/s390/include/asm/atomic_ops.h b/arch/s390/include/asm/atomic_ops.h
index ac9e2b939d04f..ba6d29412344e 100644
--- a/arch/s390/include/asm/atomic_ops.h
+++ b/arch/s390/include/asm/atomic_ops.h
@@ -111,20 +111,22 @@ __ATOMIC64_OPS(__atomic64_xor, "xgr")
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__ */
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index ffc45048ea7d7..f7838ecd83c66 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -10,6 +10,7 @@
#define __ASM_SPINLOCK_H
#include <linux/smp.h>
+#include <asm/atomic_ops.h>
#include <asm/barrier.h>
#include <asm/processor.h>
@@ -17,12 +18,6 @@
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; }
#else
@@ -40,7 +35,7 @@ bool arch_vcpu_is_preempted(int cpu);
* (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 *);
@@ -70,7 +65,7 @@ static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
{
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)
@@ -95,7 +90,7 @@ static inline int arch_spin_trylock(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)
@@ -141,16 +136,16 @@ extern int _raw_write_trylock_retry(arch_rwlock_t *lp);
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
@@ -161,9 +156,9 @@ static inline int arch_write_trylock_once(arch_rwlock_t *rw)
#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" \
@@ -175,9 +170,9 @@ static inline int arch_write_trylock_once(arch_rwlock_t *rw)
#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) \
@@ -187,14 +182,14 @@ static inline int arch_write_trylock_once(arch_rwlock_t *rw)
})
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);
}
@@ -205,7 +200,7 @@ static inline void arch_read_unlock(arch_rwlock_t *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)
@@ -232,11 +227,11 @@ static inline void arch_read_lock(arch_rwlock_t *rw)
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)
@@ -248,7 +243,7 @@ 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(
diff --git a/arch/s390/include/asm/spinlock_types.h b/arch/s390/include/asm/spinlock_types.h
index d84b6939237c1..fe755eec275f1 100644
--- a/arch/s390/include/asm/spinlock_types.h
+++ b/arch/s390/include/asm/spinlock_types.h
@@ -6,14 +6,14 @@
#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 }
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index ba427eb6f14ca..3f4d0c69bbfe1 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -32,23 +32,22 @@ static int __init spin_retry_setup(char *str)
}
__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;
}
@@ -62,7 +61,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
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)
@@ -82,9 +81,8 @@ EXPORT_SYMBOL(arch_spin_lock_wait);
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;
@@ -93,7 +91,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
/* 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;
@@ -108,7 +106,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
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)
@@ -128,18 +126,17 @@ EXPORT_SYMBOL(arch_spin_lock_wait_flags);
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;
}
@@ -147,8 +144,8 @@ EXPORT_SYMBOL(arch_spin_trylock_retry);
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);
@@ -162,12 +159,12 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
}
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;
}
}
@@ -175,17 +172,17 @@ EXPORT_SYMBOL(_raw_read_lock_wait);
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;
@@ -194,10 +191,10 @@ EXPORT_SYMBOL(_raw_read_trylock_retry);
#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) {
@@ -209,14 +206,14 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
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);
@@ -225,8 +222,8 @@ 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;
@@ -238,15 +235,15 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
}
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);
@@ -255,24 +252,24 @@ 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;
--
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