From 2eaa27dbf562d1990397db5a1022beacecedc3b8 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 27 Jun 2011 09:03:47 +0200 Subject: [PATCH] cfq-iosched: fix a rcu warning 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 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/cfq-iosched.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 6b481a6af9d8..d6da39b4fd31 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2537,11 +2537,14 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd, 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]); -- 2.39.5