| From 1a0adb9869dac631ed5d45d0afed72cfce0d9d66 Mon Sep 17 00:00:00 2001 |
| From: Jan Blunck <jblunck@suse.de> |
| Date: Fri, 3 Jul 2009 13:16:23 -0500 |
| Subject: [PATCH] rt: Make rt_down_read_trylock() behave like down_read_trylock() |
| |
| commit 1a0adb9869dac631ed5d45d0afed72cfce0d9d66 in tip. |
| |
| 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@suse.de> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| |
| diff --git a/kernel/rt.c b/kernel/rt.c |
| index 97709a6..d095969 100644 |
| --- a/kernel/rt.c |
| +++ b/kernel/rt.c |
| @@ -380,18 +380,6 @@ int rt_down_read_trylock(struct rw_semaphore *rwsem) |
| 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_); |
| -- |
| 1.7.1.1 |
| |
