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Commit 620de546 authored by David S. Miller's avatar David S. Miller
Browse files

[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: default avatarDavid S. Miller <davem@davemloft.net>
parent 6593eaed

include/asm-sparc64/rwsem.h

+4 −44
Original line number Original line Diff line number Diff line
@@ -46,54 +46,14 @@ extern void __up_read(struct rw_semaphore *sem); 
extern void __up_write(struct rw_semaphore *sem);

extern void __up_write(struct rw_semaphore *sem);

extern void __downgrade_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;

	return atomic_add_return(delta, (atomic_t *)(&sem->count));



	__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;

}



#define rwsem_atomic_add rwsem_atomic_update



static __inline__ __u16 rwsem_cmpxchgw(struct rw_semaphore *sem, __u16 __old, __u16 __new)

{

	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)

static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)

{

{

	return cmpxchg(&sem->count,old,new);

	atomic_add(delta, (atomic_t *)(&sem->count));

}

}





#endif /* __KERNEL__ */

#endif /* __KERNEL__ */