From: Shaohua Li <shaohua.li@intel.com>
To: lkml <linux-kernel@vger.kernel.org>
Cc: Jens Axboe <jaxboe@fusionio.com>
Subject: [patch 1/2]cfq-iosched: fix a rcu warning
Date: Mon, 27 Jun 2011 14:52:37 +0800 [thread overview]
Message-ID: <1309157557.15392.176.camel@sli10-conroe> (raw)
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>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f379943..fd566c1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2773,11 +2773,14 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
smp_wmb();
cic->key = cfqd_dead_key(cfqd);
+ 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]);
reply other threads:[~2011-06-27 6:53 UTC|newest]
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