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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>
This commit is contained in:
Kirill Tkhai 2017-09-29 19:06:38 +03:00 committed by Ingo Molnar
parent 19c6092301
commit 76f8507f7a
3 changed files with 27 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/asm-generic/rwsem.h
View File

@ -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;

1
include/linux/rwsem.h
View File

@ -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

16
kernel/locking/rwsem.c
View File

@ -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
*/