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parisc: Improve spinlock handling 

Use READ_ONCE() to check if spinlock is locked.
The other changes are cleanups.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
John David Anglin 2020-10-02 21:41:52 +02:00 committed by Helge Deller
parent b47cf49746
commit f173e3a751
1 changed files with 13 additions and 10 deletions
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23
arch/parisc/include/asm/spinlock.h
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@ -10,13 +10,21 @@
static inline int arch_spin_is_locked(arch_spinlock_t *x) static inline int arch_spin_is_locked(arch_spinlock_t *x)
{ {
volatile unsigned int *a = __ldcw_align(x); volatile unsigned int *a = __ldcw_align(x);
return *a == 0; return READ_ONCE(*a) == 0;
} }
#define arch_spin_lock(lock) arch_spin_lock_flags(lock, 0) static inline void arch_spin_lock(arch_spinlock_t *x)
{
volatile unsigned int *a;
a = __ldcw_align(x);
while (__ldcw(a) == 0)
while (*a == 0)
continue;
}
static inline void arch_spin_lock_flags(arch_spinlock_t *x, static inline void arch_spin_lock_flags(arch_spinlock_t *x,
unsigned long flags) unsigned long flags)
{ {
volatile unsigned int *a; volatile unsigned int *a;
@ -25,10 +33,8 @@ static inline void arch_spin_lock_flags(arch_spinlock_t *x,
while (*a == 0) while (*a == 0)
if (flags & PSW_SM_I) { if (flags & PSW_SM_I) {
local_irq_enable(); local_irq_enable();
cpu_relax();
local_irq_disable(); local_irq_disable();
} else }
cpu_relax();
} }
#define arch_spin_lock_flags arch_spin_lock_flags #define arch_spin_lock_flags arch_spin_lock_flags
@ -44,12 +50,9 @@ static inline void arch_spin_unlock(arch_spinlock_t *x)
static inline int arch_spin_trylock(arch_spinlock_t *x) static inline int arch_spin_trylock(arch_spinlock_t *x)
{ {
volatile unsigned int *a; volatile unsigned int *a;
int ret;
a = __ldcw_align(x); a = __ldcw_align(x);
ret = __ldcw(a) != 0; return __ldcw(a) != 0;
return ret;
} }
/* /*