aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/lib
diff options
context:
space:
mode:
authorPhilipp Hachtmann <phacht@linux.vnet.ibm.com>2014-04-07 18:25:23 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-05-20 08:58:41 +0200
commit5b3f683e694a835f5dfdab06102be1a50604c3b7 (patch)
treed9f1b030cd5d211c2a014194a288ad807f20308e /arch/s390/lib
parent50be634507284eea38df78154d22615d21200b42 (diff)
downloadlinux-linaro-stable-5b3f683e694a835f5dfdab06102be1a50604c3b7.tar.gz
s390/spinlock: cleanup spinlock code
Improve the spinlock code in several aspects: - Have _raw_compare_and_swap return true if the operation has been successful instead of returning the old value. - Remove the "volatile" from arch_spinlock_t and arch_rwlock_t - Rename 'owner_cpu' to 'lock' - Add helper functions arch_spin_trylock_once / arch_spin_tryrelease_once [ Martin Schwidefsky: patch breakdown and code beautification ] Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/lib')
-rw-r--r--arch/s390/lib/spinlock.c55
1 files changed, 26 insertions, 29 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index f709983f41f8..4a3b33b2dbb9 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -31,22 +31,21 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
unsigned int owner;
while (1) {
- owner = lp->owner_cpu;
+ owner = lp->lock;
if (!owner || smp_vcpu_scheduled(~owner)) {
for (count = spin_retry; count > 0; count--) {
if (arch_spin_is_locked(lp))
continue;
- if (_raw_compare_and_swap(&lp->owner_cpu, 0,
- cpu) == 0)
+ if (_raw_compare_and_swap(&lp->lock, 0, cpu))
return;
}
if (MACHINE_IS_LPAR)
continue;
}
- owner = lp->owner_cpu;
+ owner = lp->lock;
if (owner)
smp_yield_cpu(~owner);
- if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
+ if (_raw_compare_and_swap(&lp->lock, 0, cpu))
return;
}
}
@@ -60,57 +59,55 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
local_irq_restore(flags);
while (1) {
- owner = lp->owner_cpu;
+ owner = lp->lock;
if (!owner || smp_vcpu_scheduled(~owner)) {
for (count = spin_retry; count > 0; count--) {
if (arch_spin_is_locked(lp))
continue;
local_irq_disable();
- if (_raw_compare_and_swap(&lp->owner_cpu, 0,
- cpu) == 0)
+ if (_raw_compare_and_swap(&lp->lock, 0, cpu))
return;
local_irq_restore(flags);
}
if (MACHINE_IS_LPAR)
continue;
}
- owner = lp->owner_cpu;
+ owner = lp->lock;
if (owner)
smp_yield_cpu(~owner);
local_irq_disable();
- if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
+ if (_raw_compare_and_swap(&lp->lock, 0, cpu))
return;
local_irq_restore(flags);
}
}
EXPORT_SYMBOL(arch_spin_lock_wait_flags);
+void arch_spin_relax(arch_spinlock_t *lp)
+{
+ unsigned int cpu = lp->lock;
+ if (cpu != 0) {
+ if (MACHINE_IS_VM || MACHINE_IS_KVM ||
+ !smp_vcpu_scheduled(~cpu))
+ smp_yield_cpu(~cpu);
+ }
+}
+EXPORT_SYMBOL(arch_spin_relax);
+
int arch_spin_trylock_retry(arch_spinlock_t *lp)
{
- unsigned int cpu = ~smp_processor_id();
int count;
for (count = spin_retry; count > 0; count--) {
if (arch_spin_is_locked(lp))
continue;
- if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
+ if (arch_spin_trylock_once(lp))
return 1;
}
return 0;
}
EXPORT_SYMBOL(arch_spin_trylock_retry);
-void arch_spin_relax(arch_spinlock_t *lock)
-{
- unsigned int cpu = lock->owner_cpu;
- if (cpu != 0) {
- if (MACHINE_IS_VM || MACHINE_IS_KVM ||
- !smp_vcpu_scheduled(~cpu))
- smp_yield_cpu(~cpu);
- }
-}
-EXPORT_SYMBOL(arch_spin_relax);
-
void _raw_read_lock_wait(arch_rwlock_t *rw)
{
unsigned int old;
@@ -124,7 +121,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
if (!arch_read_can_lock(rw))
continue;
old = rw->lock & 0x7fffffffU;
- if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return;
}
}
@@ -145,7 +142,7 @@ void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
continue;
old = rw->lock & 0x7fffffffU;
local_irq_disable();
- if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return;
}
}
@@ -160,7 +157,7 @@ int _raw_read_trylock_retry(arch_rwlock_t *rw)
if (!arch_read_can_lock(rw))
continue;
old = rw->lock & 0x7fffffffU;
- if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return 1;
}
return 0;
@@ -178,7 +175,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
}
if (!arch_write_can_lock(rw))
continue;
- if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+ if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return;
}
}
@@ -197,7 +194,7 @@ void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
if (!arch_write_can_lock(rw))
continue;
local_irq_disable();
- if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+ if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return;
}
}
@@ -210,7 +207,7 @@ int _raw_write_trylock_retry(arch_rwlock_t *rw)
while (count-- > 0) {
if (!arch_write_can_lock(rw))
continue;
- if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+ if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return 1;
}
return 0;