Messages in this thread Patch in this message | | | Date | Sun, 05 Feb 2012 23:10:18 +0100 | From | Willy Tarreau <> | Subject | [PATCH 29/91] cfq-iosched: fix a rcu warning |
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2.6.27-longterm review patch. If anyone has any objections, please let us know.
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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 files changed, 4 insertions(+), 1 deletions(-)
Index: longterm-2.6.27/block/cfq-iosched.c =================================================================== --- longterm-2.6.27.orig/block/cfq-iosched.c 2012-02-05 22:34:38.850917663 +0100 +++ longterm-2.6.27/block/cfq-iosched.c 2012-02-05 22:34:38.987917155 +0100 @@ -1286,11 +1286,14 @@ 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[ASYNC]) { cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
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