Now that we guarantee hb queue and rt_mutex waiter state match up, we
no longer need to deal with the fallout of when they don't.
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
kernel/futex.c | 38 +-------------------------------------
1 file changed, 1 insertion(+), 37 deletions(-)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1396,13 +1396,7 @@ static int wake_futex_pi(u32 __user *uad
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
- /*
- * It is possible that the next waiter (the one that brought
- * top_waiter owner to the kernel) timed out and is no longer
- * waiting on the lock.
- */
- if (!new_owner)
- new_owner = top_waiter->task;
+ BUG_ON(!new_owner);
/*
* We pass it to the next owner. The WAITERS bit is always
@@ -2324,7 +2318,6 @@ static long futex_wait_restart(struct re
*/
static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
{
- struct task_struct *owner;
int ret = 0;
if (locked) {
@@ -2337,35 +2330,6 @@ static int fixup_owner(u32 __user *uaddr
goto out;
}
- /*
- * Catch the rare case, where the lock was released when we were on the
- * way back before we locked the hash bucket.
- */
- if (q->pi_state->owner == current) {
- /*
- * Try to get the rt_mutex now. This might fail as some other
- * task acquired the rt_mutex after we removed ourself from the
- * rt_mutex waiters list.
- */
- if (rt_mutex_futex_trylock(&q->pi_state->pi_mutex)) {
- locked = 1;
- goto out;
- }
-
- /*
- * pi_state is incorrect, some other task did a lock steal and
- * we returned due to timeout or signal without taking the
- * rt_mutex. Too late.
- */
- raw_spin_lock_irq(&q->pi_state->pi_mutex.wait_lock);
- owner = rt_mutex_owner(&q->pi_state->pi_mutex);
- if (!owner)
- owner = rt_mutex_next_owner(&q->pi_state->pi_mutex);
- raw_spin_unlock_irq(&q->pi_state->pi_mutex.wait_lock);
- ret = fixup_pi_state_owner(uaddr, q, owner);
- goto out;
- }
-
/*
* Paranoia check. If we did not take the lock, then we should not be
* the owner of the rt_mutex.
