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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: Michal 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Michal Hocko 2016-04-07 17:12:25 +02:00 committed by Ingo Molnar
parent e4a2b01ed3
commit 938072e32c
2 changed files with 1 additions and 119 deletions
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1
arch/sparc/include/asm/Kbuild
View File

@ -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

119
arch/sparc/include/asm/rwsem.h
View File

@ -1,119 +0,0 @@
/*
* 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 */