diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-12-03 14:11:13 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-09 13:44:55 +0100 |
| commit | d390fc97df62dd76770eeab53f78e8ce2a07113d (patch) | |
| tree | 71289f2ba8a2fe91f05891ff513a917054c436df /kernel/locking | |
| parent | 1b75a263fbd95f7e03af23921eb3f32086db66f1 (diff) | |
rwsem: Implement down_read_interruptible
[ Upstream commit 31784cff7ee073b34d6eddabb95e3be2880a425c ]
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_interruptible. This is needed for perf_event_open to be
converted (with no semantic changes) from working on a mutex to
wroking on a rwsem.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87k0tybqfy.fsf@x220.int.ebiederm.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/rwsem.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 2ce13f958577..a5eb87f2c581 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1348,6 +1348,18 @@ inline void __down_read(struct rw_semaphore *sem) } } +static inline int __down_read_interruptible(struct rw_semaphore *sem) +{ + if (!rwsem_read_trylock(sem)) { + if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE))) + return -EINTR; + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); + } else { + rwsem_set_reader_owned(sem); + } + return 0; +} + static inline int __down_read_killable(struct rw_semaphore *sem) { if (!rwsem_read_trylock(sem)) { @@ -1498,6 +1510,20 @@ void __sched down_read(struct rw_semaphore *sem) } EXPORT_SYMBOL(down_read); +int __sched down_read_interruptible(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_interruptible)) { + rwsem_release(&sem->dep_map, _RET_IP_); + return -EINTR; + } + + return 0; +} +EXPORT_SYMBOL(down_read_interruptible); + int __sched down_read_killable(struct rw_semaphore *sem) { might_sleep(); |