[RFC 09/12] xtensa, rwsem: provide __down_write_killable

From: Michal Hocko
Date: Tue Feb 02 2016 - 15:22:33 EST


From: Michal Hocko <mhocko@xxxxxxxx>

which is uses the same fast path as __down_write except it falls back to
rwsem_down_write_failed_killable slow path and return -EINTR if killed.

Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
arch/xtensa/include/asm/rwsem.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/xtensa/include/asm/rwsem.h b/arch/xtensa/include/asm/rwsem.h
index 593483f6e1ff..6283823b8040 100644
--- a/arch/xtensa/include/asm/rwsem.h
+++ b/arch/xtensa/include/asm/rwsem.h
@@ -59,6 +59,19 @@ static inline void __down_write(struct rw_semaphore *sem)
rwsem_down_write_failed(sem);
}

+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+ int tmp;
+
+ tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
+ (atomic_t *)(&sem->count));
+ if (tmp != RWSEM_ACTIVE_WRITE_BIAS)
+ if (IS_ERR(rwsem_down_write_failed_killable(sem)))
+ return -EINTR;
+
+ return 0;
+}
+
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
int tmp;
--
2.7.0