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Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/spinlock.h50
-rw-r--r--arch/s390/lib/spinlock.c29
2 files changed, 46 insertions, 33 deletions
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 5a0b2882ad4..96879f7ad6d 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -59,7 +59,9 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lp)
static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
{
- return _raw_compare_and_swap(&lp->lock, 0, SPINLOCK_LOCKVAL);
+ barrier();
+ return likely(arch_spin_value_unlocked(*lp) &&
+ _raw_compare_and_swap(&lp->lock, 0, SPINLOCK_LOCKVAL));
}
static inline int arch_spin_tryrelease_once(arch_spinlock_t *lp)
@@ -69,20 +71,20 @@ static inline int arch_spin_tryrelease_once(arch_spinlock_t *lp)
static inline void arch_spin_lock(arch_spinlock_t *lp)
{
- if (unlikely(!arch_spin_trylock_once(lp)))
+ if (!arch_spin_trylock_once(lp))
arch_spin_lock_wait(lp);
}
static inline void arch_spin_lock_flags(arch_spinlock_t *lp,
unsigned long flags)
{
- if (unlikely(!arch_spin_trylock_once(lp)))
+ if (!arch_spin_trylock_once(lp))
arch_spin_lock_wait_flags(lp, flags);
}
static inline int arch_spin_trylock(arch_spinlock_t *lp)
{
- if (unlikely(!arch_spin_trylock_once(lp)))
+ if (!arch_spin_trylock_once(lp))
return arch_spin_trylock_retry(lp);
return 1;
}
@@ -128,19 +130,29 @@ extern void _raw_write_lock_wait(arch_rwlock_t *lp);
extern void _raw_write_lock_wait_flags(arch_rwlock_t *lp, unsigned long flags);
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));
+}
+
+static inline int arch_write_trylock_once(arch_rwlock_t *rw)
+{
+ unsigned int old = ACCESS_ONCE(rw->lock);
+ return likely(old == 0 &&
+ _raw_compare_and_swap(&rw->lock, 0, 0x80000000));
+}
+
static inline void arch_read_lock(arch_rwlock_t *rw)
{
- unsigned int old;
- old = rw->lock & 0x7fffffffU;
- if (!_raw_compare_and_swap(&rw->lock, old, old + 1))
+ if (!arch_read_trylock_once(rw))
_raw_read_lock_wait(rw);
}
static inline void arch_read_lock_flags(arch_rwlock_t *rw, unsigned long flags)
{
- unsigned int old;
- old = rw->lock & 0x7fffffffU;
- if (!_raw_compare_and_swap(&rw->lock, old, old + 1))
+ if (!arch_read_trylock_once(rw))
_raw_read_lock_wait_flags(rw, flags);
}
@@ -155,13 +167,13 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)
static inline void arch_write_lock(arch_rwlock_t *rw)
{
- if (unlikely(!_raw_compare_and_swap(&rw->lock, 0, 0x80000000)))
+ if (!arch_write_trylock_once(rw))
_raw_write_lock_wait(rw);
}
static inline void arch_write_lock_flags(arch_rwlock_t *rw, unsigned long flags)
{
- if (unlikely(!_raw_compare_and_swap(&rw->lock, 0, 0x80000000)))
+ if (!arch_write_trylock_once(rw))
_raw_write_lock_wait_flags(rw, flags);
}
@@ -172,18 +184,16 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
static inline int arch_read_trylock(arch_rwlock_t *rw)
{
- unsigned int old;
- old = rw->lock & 0x7fffffffU;
- if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1)))
- return 1;
- return _raw_read_trylock_retry(rw);
+ if (!arch_read_trylock_once(rw))
+ return _raw_read_trylock_retry(rw);
+ return 1;
}
static inline int arch_write_trylock(arch_rwlock_t *rw)
{
- if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000)))
- return 1;
- return _raw_write_trylock_retry(rw);
+ if (!arch_write_trylock_once(rw))
+ return _raw_write_trylock_retry(rw);
+ return 1;
}
#define arch_read_relax(lock) cpu_relax()
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 3f0e682b7e6..284d879a9b8 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -100,12 +100,9 @@ int arch_spin_trylock_retry(arch_spinlock_t *lp)
{
int count;
- for (count = spin_retry; count > 0; count--) {
- if (arch_spin_is_locked(lp))
- continue;
+ for (count = spin_retry; count > 0; count--)
if (arch_spin_trylock_once(lp))
return 1;
- }
return 0;
}
EXPORT_SYMBOL(arch_spin_trylock_retry);
@@ -120,9 +117,9 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
smp_yield();
count = spin_retry;
}
- if (!arch_read_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if ((int) old < 0)
continue;
- old = rw->lock & 0x7fffffffU;
if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return;
}
@@ -140,9 +137,9 @@ void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
smp_yield();
count = spin_retry;
}
- if (!arch_read_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if ((int) old < 0)
continue;
- old = rw->lock & 0x7fffffffU;
local_irq_disable();
if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return;
@@ -156,9 +153,9 @@ int _raw_read_trylock_retry(arch_rwlock_t *rw)
int count = spin_retry;
while (count-- > 0) {
- if (!arch_read_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if ((int) old < 0)
continue;
- old = rw->lock & 0x7fffffffU;
if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return 1;
}
@@ -168,6 +165,7 @@ EXPORT_SYMBOL(_raw_read_trylock_retry);
void _raw_write_lock_wait(arch_rwlock_t *rw)
{
+ unsigned int old;
int count = spin_retry;
while (1) {
@@ -175,7 +173,8 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
smp_yield();
count = spin_retry;
}
- if (!arch_write_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if (old)
continue;
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return;
@@ -185,6 +184,7 @@ EXPORT_SYMBOL(_raw_write_lock_wait);
void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
{
+ unsigned int old;
int count = spin_retry;
local_irq_restore(flags);
@@ -193,7 +193,8 @@ void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
smp_yield();
count = spin_retry;
}
- if (!arch_write_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if (old)
continue;
local_irq_disable();
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
@@ -204,10 +205,12 @@ EXPORT_SYMBOL(_raw_write_lock_wait_flags);
int _raw_write_trylock_retry(arch_rwlock_t *rw)
{
+ unsigned int old;
int count = spin_retry;
while (count-- > 0) {
- if (!arch_write_can_lock(rw))
+ old = ACCESS_ONCE(rw->lock);
+ if (old)
continue;
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return 1;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-24 01:00:21 +0000