blk-mq: Fix NULL pointer updating nr_requests

A h/w context's tags are freed if it was not assigned a CPU. Check if
the context has tags before updating the depth.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f539a53..5667f59 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2336,6 +2336,8 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 
        ret = 0;
        queue_for_each_hw_ctx(q, hctx, i) {
+               if (!hctx->tags)
+                       continue;
                ret = blk_mq_tag_update_depth(hctx->tags, nr);
                if (ret)
                        break;