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s390/spinlock: use atomic primitives for spinlocks

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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>
This commit is contained in:
Martin Schwidefsky 2016-11-28 15:50:48 +01:00
parent df26c2e87e
commit 02c503ff23
4 changed files with 70 additions and 76 deletions
Download patch file Download diff file Expand all files Collapse all files

73
arch/s390/lib/spinlock.c
View file

@ -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;