This is a note to let you know that I've just added the patch titled
cfq-iosched: fix a rcu warning
to the 2.6.33-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.33.git;a=summary
The filename of the patch is:
cfq-iosched-fix-a-rcu-warning.patch
and it can be found in the queue-2.6.33 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.33 longterm
tree,
please let <[email protected]> know about it.
>From 3181faa85bda3dc3f5e630a1846526c9caaa38e3 Mon Sep 17 00:00:00 2001
From: Shaohua Li <[email protected]>
Date: Mon, 27 Jun 2011 09:03:47 +0200
Subject: cfq-iosched: fix a rcu warning
From: Shaohua Li <[email protected]>
commit 3181faa85bda3dc3f5e630a1846526c9caaa38e3 upstream.
I got a rcu warnning at boot. the ioc->ioc_data is rcu_deferenced, but
doesn't hold rcu_read_lock.
Signed-off-by: Shaohua Li <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
block/cfq-iosched.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2537,11 +2537,14 @@ static void __cfq_exit_single_io_context
cic->dead_key = (unsigned long) cic->key;
cic->key = NULL;
+ rcu_read_lock();
if (rcu_dereference(ioc->ioc_data) == cic) {
+ rcu_read_unlock();
spin_lock(&ioc->lock);
rcu_assign_pointer(ioc->ioc_data, NULL);
spin_unlock(&ioc->lock);
- }
+ } else
+ rcu_read_unlock();
if (cic->cfqq[BLK_RW_ASYNC]) {
cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
Patches currently in longterm-queue-2.6.33 which might be from
[email protected] are
/home/gregkh/linux/longterm/longterm-queue-2.6.33/queue-2.6.33/cfq-iosched-fix-a-rcu-warning.patch
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