/*
* We're out of tags on this hardware queue, kick any
* pending IO submits before going to sleep waiting for
- * some to complete.
+ * some to complete. Note that hctx can be NULL here for
+ * reserved tag allocation.
*/
- blk_mq_run_hw_queue(hctx, false);
+ if (hctx)
+ blk_mq_run_hw_queue(hctx, false);
/*
* Retry tag allocation after running the hardware queue,