[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>
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@ -46,54 +46,14 @@ extern void __up_read(struct rw_semaphore *sem);
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extern void __up_write(struct rw_semaphore *sem);
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extern void __up_write(struct rw_semaphore *sem);
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extern void __downgrade_write(struct rw_semaphore *sem);
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extern void __downgrade_write(struct rw_semaphore *sem);
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static __inline__ int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
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static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
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{
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{
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int tmp = delta;
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return atomic_add_return(delta, (atomic_t *)(&sem->count));
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__asm__ __volatile__(
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"1:\tlduw [%2], %%g1\n\t"
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"add %%g1, %1, %%g7\n\t"
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"cas [%2], %%g1, %%g7\n\t"
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"cmp %%g1, %%g7\n\t"
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"membar #StoreLoad | #StoreStore\n\t"
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"bne,pn %%icc, 1b\n\t"
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" nop\n\t"
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"mov %%g7, %0\n\t"
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: "=&r" (tmp)
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: "0" (tmp), "r" (sem)
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: "g1", "g7", "memory", "cc");
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return tmp + delta;
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}
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}
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#define rwsem_atomic_add rwsem_atomic_update
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static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
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static __inline__ __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 __old, __u16 __new)
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{
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{
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u32 old = (sem->count & 0xffff0000) | (u32) __old;
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atomic_add(delta, (atomic_t *)(&sem->count));
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u32 new = (old & 0xffff0000) | (u32) __new;
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u32 prev;
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again:
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__asm__ __volatile__("cas [%2], %3, %0\n\t"
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"membar #StoreLoad | #StoreStore"
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: "=&r" (prev)
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: "0" (new), "r" (sem), "r" (old)
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: "memory");
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/* To give the same semantics as x86 cmpxchgw, keep trying
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* if only the upper 16-bits changed.
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*/
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if (prev != old &&
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((prev & 0xffff) == (old & 0xffff)))
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goto again;
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return prev & 0xffff;
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}
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static __inline__ signed long rwsem_cmpxchg(struct rw_semaphore *sem, signed long old, signed long new)
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{
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return cmpxchg(&sem->count,old,new);
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}
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}
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#endif /* __KERNEL__ */
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#endif /* __KERNEL__ */
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