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Commit 3aa2591d authored by Michal Hocko's avatar Michal Hocko Committed by Ingo Molnar
Browse files

locking/rwsem, xtensa: Drop superfluous arch specific implementation 



Since "locking, rwsem: drop explicit memory barriers" the arch specific
code is basically same as the the generic one so we can drop the
superfluous code.

Suggested-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarMax Filippov <jcmvbkbc@gmail.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: 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/1460041951-22347-4-git-send-email-mhocko@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2e927c64

arch/xtensa/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ generic-y += mm-arch-hooks.h 
generic-y += percpu.h

generic-y += preempt.h

generic-y += resource.h

generic-y += rwsem.h

generic-y += sections.h

generic-y += siginfo.h

generic-y += statfs.h

arch/xtensa/include/asm/rwsem.h

deleted100644 → 0
+0 −121
Original line number Diff line number Diff line 
/*

 * include/asm-xtensa/rwsem.h

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Largely copied from include/asm-ppc/rwsem.h

 *

 * Copyright (C) 2001 - 2005 Tensilica Inc.

 */



#ifndef _XTENSA_RWSEM_H

#define _XTENSA_RWSEM_H



#ifndef _LINUX_RWSEM_H

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

#endif



#define RWSEM_UNLOCKED_VALUE		0x00000000

#define RWSEM_ACTIVE_BIAS		0x00000001

#define RWSEM_ACTIVE_MASK		0x0000ffff

#define RWSEM_WAITING_BIAS		(-0x00010000)

#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 (atomic_add_return(1,(atomic_t *)(&sem->count)) <= 0)

		rwsem_down_read_failed(sem);

}



static inline int __down_read_trylock(struct rw_semaphore *sem)

{

	int tmp;



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

		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)

{

	int tmp;



	tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,

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

	if (tmp != RWSEM_ACTIVE_WRITE_BIAS)

		rwsem_down_write_failed(sem);

}



static inline int __down_write_trylock(struct rw_semaphore *sem)

{

	int 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)

{

	int tmp;



	tmp = atomic_sub_return(1,(atomic_t *)(&sem->count));

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

		rwsem_wake(sem);

}



/*

 * unlock after writing

 */

static inline void __up_write(struct rw_semaphore *sem)

{

	if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,

			      (atomic_t *)(&sem->count)) < 0)

		rwsem_wake(sem);

}



/*

 * implement atomic add functionality

 */

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

{

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

}



/*

 * downgrade write lock to read lock

 */

static inline void __downgrade_write(struct rw_semaphore *sem)

{

	int tmp;



	tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));

	if (tmp < 0)

		rwsem_downgrade_wake(sem);

}



/*

 * implement exchange and add functionality

 */

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

{

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

}



#endif	/* _XTENSA_RWSEM_H */