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| author |   Eric W. Biederman <ebiederm@xmission.com> | 2020-12-03 14:10:32 -0600 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2020-12-09 17:08:41 +0100 |
| commit | 0f9368b5bf6db0c04afc5454b1be79022a681615 (patch) | |
| tree | 9744569b45cfca2a30e6e99a5198e4ec2bbeb587 | |
| parent | Merge tag 'gfs2-v5.10-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2 (diff) | |
| download | linux-dev-0f9368b5bf6db0c04afc5454b1be79022a681615.tar.xz linux-dev-0f9368b5bf6db0c04afc5454b1be79022a681615.zip | |
rwsem: Implement down_read_killable_nested
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_killable_nested. This is needed so that kcmp_lock
can be converted from working on a mutexes to working on rw_semaphores.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87o8jabqh3.fsf@x220.int.ebiederm.org
| -rw-r--r-- | include/linux/rwsem.h | 2 | ||||
| -rw-r--r-- | kernel/locking/rwsem.c | 14 |
2 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 25e3fde85617..13021b08b2ed 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -171,6 +171,7 @@ extern void downgrade_write(struct rw_semaphore *sem); * See Documentation/locking/lockdep-design.rst for more details.) */ extern void down_read_nested(struct rw_semaphore *sem, int subclass); +extern int __must_check down_read_killable_nested(struct rw_semaphore *sem, int subclass); extern void down_write_nested(struct rw_semaphore *sem, int subclass); extern int down_write_killable_nested(struct rw_semaphore *sem, int subclass); extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock); @@ -191,6 +192,7 @@ extern void down_read_non_owner(struct rw_semaphore *sem); extern void up_read_non_owner(struct rw_semaphore *sem); #else # define down_read_nested(sem, subclass) down_read(sem) +# define down_read_killable_nested(sem, subclass) down_read_killable(sem) # define down_write_nest_lock(sem, nest_lock) down_write(sem) # define down_write_nested(sem, subclass) down_write(sem) # define down_write_killable_nested(sem, subclass) down_write_killable(sem) diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index f11b9bd3431d..54d11cb97551 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1605,6 +1605,20 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) } EXPORT_SYMBOL(down_read_nested); +int down_read_killable_nested(struct rw_semaphore *sem, int subclass) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_); + + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) { + rwsem_release(&sem->dep_map, _RET_IP_); + return -EINTR; + } + + return 0; +} +EXPORT_SYMBOL(down_read_killable_nested); + void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) { might_sleep(); |