This patch removes the stupid "Read locks within the self-held write lock
succeed" behaviour. This is breaking in mm_take_all_locks() since it is quite
common to ensure that a lock is taken with BUG_ON(down_read_trylock(&mm->mmap_sem)).
Signed-off-by: Jan Blunck <jblunck@xxxxxxx>
---
kernel/rt.c | 12 ------------
1 file changed, 12 deletions(-)
Index: b/kernel/rt.c
===================================================================
--- a/kernel/rt.c
+++ b/kernel/rt.c
@@ -381,18 +381,6 @@ int rt_down_read_trylock(struct rw_sema
unsigned long flags;
int ret;
- /*
- * Read locks within the self-held write lock succeed.
- */
- spin_lock_irqsave(&rwsem->lock.wait_lock, flags);
- if (rt_mutex_real_owner(&rwsem->lock) == current) {
- spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
- rwsem_acquire_read(&rwsem->dep_map, 0, 1, _RET_IP_);
- rwsem->read_depth++;
- return 1;
- }
- spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
-
ret = rt_mutex_trylock(&rwsem->lock);
if (ret)
rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
--
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