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atomic_*_*_nv() functions need to return the new value atomically. 

A local variable must be used for the return value to avoid a
potential race once the spin lock is dropped.

Signed-off-by: Ricardo M. Correia <ricardo.correia@oracle.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Ricardo M. Correia 2010-09-17 16:03:15 -07:00 committed by Brian Behlendorf
parent d5fcc5f51c
commit a68d91d770
1 changed files with 32 additions and 12 deletions
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44
include/sys/atomic.h
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@ -93,41 +93,51 @@ atomic_sub_32(volatile uint32_t *target, int32_t delta)
static __inline__ uint32_t static __inline__ uint32_t
atomic_inc_32_nv(volatile uint32_t *target) atomic_inc_32_nv(volatile uint32_t *target)
{ {
uint32_t nv;
spin_lock(&atomic32_lock); spin_lock(&atomic32_lock);
(*target)++; nv = ++(*target);
spin_unlock(&atomic32_lock); spin_unlock(&atomic32_lock);
return *target; return nv;
} }
static __inline__ uint32_t static __inline__ uint32_t
atomic_dec_32_nv(volatile uint32_t *target) atomic_dec_32_nv(volatile uint32_t *target)
{ {
uint32_t nv;
spin_lock(&atomic32_lock); spin_lock(&atomic32_lock);
(*target)--; nv = --(*target);
spin_unlock(&atomic32_lock); spin_unlock(&atomic32_lock);
return *target; return nv;
} }
static __inline__ uint32_t static __inline__ uint32_t
atomic_add_32_nv(volatile uint32_t *target, uint32_t delta) atomic_add_32_nv(volatile uint32_t *target, uint32_t delta)
{ {
uint32_t nv;
spin_lock(&atomic32_lock); spin_lock(&atomic32_lock);
*target += delta; *target += delta;
nv = *target;
spin_unlock(&atomic32_lock); spin_unlock(&atomic32_lock);
return *target; return nv;
} }
static __inline__ uint32_t static __inline__ uint32_t
atomic_sub_32_nv(volatile uint32_t *target, uint32_t delta) atomic_sub_32_nv(volatile uint32_t *target, uint32_t delta)
{ {
uint32_t nv;
spin_lock(&atomic32_lock); spin_lock(&atomic32_lock);
*target -= delta; *target -= delta;
nv = *target;
spin_unlock(&atomic32_lock); spin_unlock(&atomic32_lock);
return *target; return nv;
} }
static __inline__ uint32_t static __inline__ uint32_t
@ -181,41 +191,51 @@ atomic_sub_64(volatile uint64_t *target, uint64_t delta)
static __inline__ uint64_t static __inline__ uint64_t
atomic_inc_64_nv(volatile uint64_t *target) atomic_inc_64_nv(volatile uint64_t *target)
{ {
uint64_t nv;
spin_lock(&atomic64_lock); spin_lock(&atomic64_lock);
(*target)++; nv = ++(*target);
spin_unlock(&atomic64_lock); spin_unlock(&atomic64_lock);
return *target; return nv;
} }
static __inline__ uint64_t static __inline__ uint64_t
atomic_dec_64_nv(volatile uint64_t *target) atomic_dec_64_nv(volatile uint64_t *target)
{ {
uint64_t nv;
spin_lock(&atomic64_lock); spin_lock(&atomic64_lock);
(*target)--; nv = --(*target);
spin_unlock(&atomic64_lock); spin_unlock(&atomic64_lock);
return *target; return nv;
} }
static __inline__ uint64_t static __inline__ uint64_t
atomic_add_64_nv(volatile uint64_t *target, uint64_t delta) atomic_add_64_nv(volatile uint64_t *target, uint64_t delta)
{ {
uint64_t nv;
spin_lock(&atomic64_lock); spin_lock(&atomic64_lock);
*target += delta; *target += delta;
nv = *target;
spin_unlock(&atomic64_lock); spin_unlock(&atomic64_lock);
return *target; return nv;
} }
static __inline__ uint64_t static __inline__ uint64_t
atomic_sub_64_nv(volatile uint64_t *target, uint64_t delta) atomic_sub_64_nv(volatile uint64_t *target, uint64_t delta)
{ {
uint64_t nv;
spin_lock(&atomic64_lock); spin_lock(&atomic64_lock);
*target -= delta; *target -= delta;
nv = *target;
spin_unlock(&atomic64_lock); spin_unlock(&atomic64_lock);
return *target; return nv;
} }
static __inline__ uint64_t static __inline__ uint64_t