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Commit 938072e3 authored by Michal Hocko's avatar Michal Hocko Committed by Ingo Molnar
Browse files

locking/rwsem, sparc: Drop superfluous arch specific implementation 



sparc basically reuses the generic implementation of rwsem so we can
reuse the code rather than duplicate it.

Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Signed-off-by: Jason Low <jason.low2@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1460041951-22347-6-git-send-email-mhocko@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e4a2b01e

arch/sparc/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ generic-y += mm-arch-hooks.h 
generic-y += module.h

generic-y += mutex.h

generic-y += preempt.h

generic-y += rwsem.h

generic-y += serial.h

generic-y += trace_clock.h

generic-y += types.h

arch/sparc/include/asm/rwsem.h

deleted100644 → 0
+0 −119
Original line number Diff line number Diff line 
/*

 * rwsem.h: R/W semaphores implemented using CAS

 *

 * Written by David S. Miller (davem@redhat.com), 2001.

 * Derived from asm-i386/rwsem.h

 */

#ifndef _SPARC64_RWSEM_H

#define _SPARC64_RWSEM_H



#ifndef _LINUX_RWSEM_H

#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"

#endif



#ifdef __KERNEL__



#define RWSEM_UNLOCKED_VALUE		0x00000000L

#define RWSEM_ACTIVE_BIAS		0x00000001L

#define RWSEM_ACTIVE_MASK		0xffffffffL

#define RWSEM_WAITING_BIAS		(-RWSEM_ACTIVE_MASK-1)

#define RWSEM_ACTIVE_READ_BIAS		RWSEM_ACTIVE_BIAS

#define RWSEM_ACTIVE_WRITE_BIAS		(RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)



/*

 * lock for reading

 */

static inline void __down_read(struct rw_semaphore *sem)

{

	if (unlikely(atomic64_inc_return((atomic64_t *)(&sem->count)) <= 0L))

		rwsem_down_read_failed(sem);

}



static inline int __down_read_trylock(struct rw_semaphore *sem)

{

	long tmp;



	while ((tmp = sem->count) >= 0L) {

		if (tmp == cmpxchg(&sem->count, tmp,

				   tmp + RWSEM_ACTIVE_READ_BIAS)) {

			return 1;

		}

	}

	return 0;

}



/*

 * lock for writing

 */

static inline void __down_write(struct rw_semaphore *sem)

{

	long tmp;



	tmp = atomic64_add_return(RWSEM_ACTIVE_WRITE_BIAS,

				  (atomic64_t *)(&sem->count));

	if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))

		rwsem_down_write_failed(sem);

}



static inline int __down_write_trylock(struct rw_semaphore *sem)

{

	long tmp;



	tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,

		      RWSEM_ACTIVE_WRITE_BIAS);

	return tmp == RWSEM_UNLOCKED_VALUE;

}



/*

 * unlock after reading

 */

static inline void __up_read(struct rw_semaphore *sem)

{

	long tmp;



	tmp = atomic64_dec_return((atomic64_t *)(&sem->count));

	if (unlikely(tmp < -1L && (tmp & RWSEM_ACTIVE_MASK) == 0L))

		rwsem_wake(sem);

}



/*

 * unlock after writing

 */

static inline void __up_write(struct rw_semaphore *sem)

{

	if (unlikely(atomic64_sub_return(RWSEM_ACTIVE_WRITE_BIAS,

					 (atomic64_t *)(&sem->count)) < 0L))

		rwsem_wake(sem);

}



/*

 * implement atomic add functionality

 */

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

{

	atomic64_add(delta, (atomic64_t *)(&sem->count));

}



/*

 * downgrade write lock to read lock

 */

static inline void __downgrade_write(struct rw_semaphore *sem)

{

	long tmp;



	tmp = atomic64_add_return(-RWSEM_WAITING_BIAS, (atomic64_t *)(&sem->count));

	if (tmp < 0L)

		rwsem_downgrade_wake(sem);

}



/*

 * implement exchange and add functionality

 */

static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)

{

	return atomic64_add_return(delta, (atomic64_t *)(&sem->count));

}



#endif /* __KERNEL__ */



#endif /* _SPARC64_RWSEM_H */