diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-12-03 14:10:32 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-09 13:44:55 +0100 |
| commit | 1b75a263fbd95f7e03af23921eb3f32086db66f1 (patch) | |
| tree | cb8397c6ea64aad16a4a6910e749be0efe4f0b05 /kernel | |
| parent | 71b8355ba667028557a88253096d6991a11abfba (diff) | |
rwsem: Implement down_read_killable_nested
[ Upstream commit 0f9368b5bf6db0c04afc5454b1be79022a681615 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/locking/rwsem.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index baafa1dd9fcc..2ce13f958577 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1608,6 +1608,20 @@ 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(); |