On Wed, May 11, 2016 at 10:28:53AM +0200, Michal Hocko wrote:
> Does the following look correct/reasonable? This is absolutely untested
> and more for a discussion:
I would much rather see it in common; something like so perhaps.
---
kernel/locking/rwsem-xadd.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index df4dcb883b50..5d7f2831a475 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -487,11 +487,9 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem,
int state)
/* Block until there are no active lockers. */
do {
- if (signal_pending_state(state, current)) {
- raw_spin_lock_irq(&sem->wait_lock);
- ret = ERR_PTR(-EINTR);
- goto out;
- }
+ if (signal_pending_state(state, current))
+ goto out_nolock;
+
schedule();
set_current_state(state);
} while ((count = sem->count) & RWSEM_ACTIVE_MASK);
@@ -504,6 +502,18 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem,
int state)
raw_spin_unlock_irq(&sem->wait_lock);
return ret;
+
+out_nolock:
+ __set_current_state(TASK_RUNNING);
+ raw_spin_lock_irq(&sem->wait_lock);
+ list_del(&waiter.list);
+ if (list_empty(&sem->wait_list))
+ rwsem_atomic_update(-RWSEM_WAITING_BIAS, sem);
+ else
+ __rwsem_do_wake(sem, RWSEM_WAKE_READERS);
+ raw_spin_unlock_irq(&sem->wait_lock);
+
+ return ERR_PTR(-EINTR);
}
__visible struct rw_semaphore * __sched
