From 3181faa85bda3dc3f5e630a1846526c9caaa38e3 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 27 Jun 2011 09:03:47 +0200 Subject: cfq-iosched: fix a rcu warning 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 Cc: stable@kernel.org # after ab4bd22d Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'block') 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]); -- cgit v1.1 From 726e99ab88db059fe1422e15376ae404f8c66eb4 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 27 Jun 2011 09:03:48 +0200 Subject: cfq-iosched: make code consistent ioc->ioc_data is rcu protectd, so uses correct API to access it. This doesn't change any behavior, but just make code consistent. Signed-off-by: Shaohua Li Cc: stable@kernel.org # after ab4bd22d Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index fd566c1..ae21919 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3087,7 +3087,8 @@ cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, spin_lock_irqsave(&ioc->lock, flags); - BUG_ON(ioc->ioc_data == cic); + BUG_ON(rcu_dereference_check(ioc->ioc_data, + lockdep_is_held(&ioc->lock)) == cic); radix_tree_delete(&ioc->radix_root, cfqd->cic_index); hlist_del_rcu(&cic->cic_list); -- cgit v1.1