[PATCH 04/11] alpha, rwsem: provide __down_write_killable

Michal Hocko
2016-04-01T11:04:48Z

From: Michal Hocko <mhocko@suse.com>

Introduce ___down_write for the fast path and reuse it for __down_write
resp. __down_write_killable each using the respective generic slow path
(rwsem_down_write_failed resp. rwsem_down_write_failed_killable).

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
arch/alpha/include/asm/rwsem.h | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/include/asm/rwsem.h b/arch/alpha/include/asm/rwsem.h
index a83bbea62c67..0131a7058778 100644
--- a/arch/alpha/include/asm/rwsem.h
+++ b/arch/alpha/include/asm/rwsem.h
@@ -63,7 +63,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
return res >= 0 ? 1 : 0;
}

-static inline void __down_write(struct rw_semaphore *sem)
+static inline long ___down_write(struct rw_semaphore *sem)
{
long oldcount;
#ifndef CONFIG_SMP
@@ -83,10 +83,24 @@ static inline void __down_write(struct rw_semaphore *sem)
:"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
:"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
#endif
- if (unlikely(oldcount))
+ return oldcount;
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+ if (unlikely(___down_write(sem)))
rwsem_down_write_failed(sem);
}

+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+ if (unlikely(___down_write(sem)))
+ if (IS_ERR(rwsem_down_write_failed_killable(sem)))
+ return -EINTR;
+
+ return 0;
+}
+
/*
* trylock for writing -- returns 1 if successful, 0 if contention
*/
--
2.8.0.rc3