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authorEric W. Biederman <ebiederm@xmission.com>2020-12-03 23:10:32 +0300
committerPeter Zijlstra <peterz@infradead.org>2020-12-09 19:08:41 +0300
commit0f9368b5bf6db0c04afc5454b1be79022a681615 (patch)
tree9744569b45cfca2a30e6e99a5198e4ec2bbeb587 /kernel/locking
parent34816d20f173a90389c8a7e641166d8ea9dce70a (diff)
downloadlinux-0f9368b5bf6db0c04afc5454b1be79022a681615.tar.xz
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
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/rwsem.c14
1 files changed, 14 insertions, 0 deletions
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();