Messages in this thread Patch in this message | | | Date | Fri, 08 Jul 2011 16:00:31 -0700 | From | Greg KH <> | Subject | [15/35] cfq-iosched: fix a rcu warning |
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2.6.33-longterm review patch. If anyone has any objections, please let us know.
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From: Shaohua Li <shaohua.li@intel.com>
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 <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- 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]);
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