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[SPARC64]: Simplify asm/rwsem.h slightly. 

rwsem_atomic_update and rwsem_atomic_add can be implemented
straightly using atomic_*() routines.

Also, rwsem_cmpxchgw() is totally unused, kill it.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2005-07-24 19:35:42 -07:00
parent 6593eaed81
commit 620de54675
1 changed files with 4 additions and 44 deletions
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48
include/asm-sparc64/rwsem.h
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@ -46,54 +46,14 @@ extern void __up_read(struct rw_semaphore *sem);
extern void __up_write(struct rw_semaphore *sem);
extern void __downgrade_write(struct rw_semaphore *sem);
static __inline__ int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
{
int tmp = delta;
__asm__ __volatile__(
"1:\tlduw [%2], %%g1\n\t"
"add %%g1, %1, %%g7\n\t"
"cas [%2], %%g1, %%g7\n\t"
"cmp %%g1, %%g7\n\t"
"membar #StoreLoad | #StoreStore\n\t"
"bne,pn %%icc, 1b\n\t"
" nop\n\t"
"mov %%g7, %0\n\t"
: "=&r" (tmp)
: "0" (tmp), "r" (sem)
: "g1", "g7", "memory", "cc");
return tmp + delta;
return atomic_add_return(delta, (atomic_t *)(&sem->count));
}
#define rwsem_atomic_add rwsem_atomic_update
static __inline__ __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 __old, __u16 __new)
static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
{
u32 old = (sem->count & 0xffff0000) | (u32) __old;
u32 new = (old & 0xffff0000) | (u32) __new;
u32 prev;
again:
__asm__ __volatile__("cas [%2], %3, %0\n\t"
"membar #StoreLoad | #StoreStore"
: "=&r" (prev)
: "0" (new), "r" (sem), "r" (old)
: "memory");
/* To give the same semantics as x86 cmpxchgw, keep trying
* if only the upper 16-bits changed.
*/
if (prev != old &&
((prev & 0xffff) == (old & 0xffff)))
goto again;
return prev & 0xffff;
}
static __inline__ signed long rwsem_cmpxchg(struct rw_semaphore *sem, signed long old, signed long new)
{
return cmpxchg(&sem->count,old,new);
atomic_add(delta, (atomic_t *)(&sem->count));
}
#endif /* __KERNEL__ */