bfq-iosched: fix NULL ioc check in bfq_get_rq_private

icq_to_bic is a container_of operation, so we need to check for NULL
before it.  Also move the check outside the spinlock while we're at
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 4f69e39c2f89885cb84d2711eff5e9496f90eb38..f037b005faa1a541f0e55ee471c88d9a462d87a6 100644 (file)
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4398,16 +4398,17 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
                              struct bio *bio)
 {
        struct bfq_data *bfqd = q->elevator->elevator_data;
-       struct bfq_io_cq *bic = icq_to_bic(rq->elv.icq);
+       struct bfq_io_cq *bic;
        const int is_sync = rq_is_sync(rq);
        struct bfq_queue *bfqq;
        bool new_queue = false;
        bool split = false;
 
-       spin_lock_irq(&bfqd->lock);
+       if (!rq->elv.icq)
+               return 1;
+       bic = icq_to_bic(rq->elv.icq);
 
-       if (!bic)
-               goto queue_fail;
+       spin_lock_irq(&bfqd->lock);
 
        bfq_check_ioprio_change(bic, bio);
 
@@ -4465,13 +4466,7 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
                bfq_handle_burst(bfqd, bfqq);
 
        spin_unlock_irq(&bfqd->lock);
-
        return 0;
-
-queue_fail:
-       spin_unlock_irq(&bfqd->lock);
-
-       return 1;
 }
 
 static void bfq_idle_slice_timer_body(struct bfq_queue *bfqq)