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| author | Kirill Tkhai <ktkhai@virtuozzo.com> | 2017-09-29 19:06:38 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-10-10 11:50:16 +0200 |
| commit | 76f8507f7a6442215df19de74f07eabca2462f1e (patch) | |
| tree | 89d418742e8c8c6480ca3a478b77f53338bc2672 | |
| parent | 19c60923010b3f56f10ca1fb6d537c9cc852b3f1 (diff) | |
| download | op-kernel-dev-76f8507f7a6442215df19de74f07eabca2462f1e.zip op-kernel-dev-76f8507f7a6442215df19de74f07eabca2462f1e.tar.gz | |
locking/rwsem: Add down_read_killable()
Similar to down_read() and down_write_killable(),
add killable version of down_read(), based on
__down_read_killable() function, added in previous
patches.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: avagin@virtuozzo.com
Cc: davem@davemloft.net
Cc: fenghua.yu@intel.com
Cc: gorcunov@virtuozzo.com
Cc: heiko.carstens@de.ibm.com
Cc: hpa@zytor.com
Cc: ink@jurassic.park.msu.ru
Cc: mattst88@gmail.com
Cc: rientjes@google.com
Cc: rth@twiddle.net
Cc: schwidefsky@de.ibm.com
Cc: tony.luck@intel.com
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/150670119884.23930.2585570605960763239.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | include/asm-generic/rwsem.h | 10 | ||||
| -rw-r--r-- | include/linux/rwsem.h | 1 | ||||
| -rw-r--r-- | kernel/locking/rwsem.c | 16 |
3 files changed, 27 insertions, 0 deletions
diff --git a/include/asm-generic/rwsem.h b/include/asm-generic/rwsem.h index 6c6a214..b2d68d2 100644 --- a/include/asm-generic/rwsem.h +++ b/include/asm-generic/rwsem.h @@ -37,6 +37,16 @@ static inline void __down_read(struct rw_semaphore *sem) rwsem_down_read_failed(sem); } +static inline int __down_read_killable(struct rw_semaphore *sem) +{ + if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { + if (IS_ERR(rwsem_down_read_failed_killable(sem))) + return -EINTR; + } + + return 0; +} + static inline int __down_read_trylock(struct rw_semaphore *sem) { long tmp; diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 0ad7318..6ac8ee5 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -111,6 +111,7 @@ static inline int rwsem_is_contended(struct rw_semaphore *sem) * lock for reading */ extern void down_read(struct rw_semaphore *sem); +extern int __must_check down_read_killable(struct rw_semaphore *sem); /* * trylock for reading -- returns 1 if successful, 0 if contention diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 4d48b1c..e53f7746 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -28,6 +28,22 @@ void __sched down_read(struct rw_semaphore *sem) EXPORT_SYMBOL(down_read); +int __sched down_read_killable(struct rw_semaphore *sem) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); + + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) { + rwsem_release(&sem->dep_map, 1, _RET_IP_); + return -EINTR; + } + + rwsem_set_reader_owned(sem); + return 0; +} + +EXPORT_SYMBOL(down_read_killable); + /* * trylock for reading -- returns 1 if successful, 0 if contention */ |
