From a83b576c9c25cf771fb0b15ec5eb2e7510ec2f5a Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 21 Mar 2017 17:20:01 -0600 Subject: block: fix stacked driver stats init and free If a driver allocates a queue for stacked usage, then it does not currently get stats allocated. This causes the later init of, eg, writeback throttling to blow up. Move the init to the queue allocation instead. Additionally, allow a NULL callback unregistration. This avoids having the caller check for that, fixing another oops on removal of a block device that doesn't have poll stats allocated. Fixes: 34dbad5d26e2 ("blk-stat: convert to callback-based statistics reporting") Signed-off-by: Jens Axboe --- block/blk-stat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block/blk-stat.c') diff --git a/block/blk-stat.c b/block/blk-stat.c index 0d8721a60db9..188b535cf4d6 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -210,7 +210,8 @@ static void blk_stat_free_callback_rcu(struct rcu_head *head) void blk_stat_free_callback(struct blk_stat_callback *cb) { - call_rcu(&cb->rcu, blk_stat_free_callback_rcu); + if (cb) + call_rcu(&cb->rcu, blk_stat_free_callback_rcu); } EXPORT_SYMBOL_GPL(blk_stat_free_callback); -- cgit