diff options
Diffstat (limited to 'block/blk-sysfs.c')
| -rw-r--r-- | block/blk-sysfs.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 4db5abf96b9e..521ae9089c50 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -551,11 +551,20 @@ int blk_register_queue(struct gendisk *disk) return -ENXIO; /* - * Initialization must be complete by now. Finish the initial - * bypass from queue allocation. + * SCSI probing may synchronously create and destroy a lot of + * request_queues for non-existent devices. Shutting down a fully + * functional queue takes measureable wallclock time as RCU grace + * periods are involved. To avoid excessive latency in these + * cases, a request_queue starts out in a degraded mode which is + * faster to shut down and is made fully functional here as + * request_queues for non-existent devices never get registered. */ - queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q); - blk_queue_bypass_end(q); + if (!blk_queue_init_done(q)) { + queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q); + blk_queue_bypass_end(q); + if (q->mq_ops) + blk_mq_finish_init(q); + } ret = blk_trace_init_sysfs(dev); if (ret) |