block: shortcut __submit_bio_noacct for blk-mq drivers

For blk-mq drivers bios can only be inserted for the same queue.  So
bypass the complicated sorting logic in __submit_bio_noacct with
a blk-mq simpler submission helper.

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

diff --git a/block/blk-core.c b/block/blk-core.c
index 57b5dc00d44cb1052b90dacb426202bf897c2360..2ff166f0d24ee3861933356656a08ff4a6b139ec 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1152,6 +1152,34 @@ static blk_qc_t __submit_bio_noacct(struct bio *bio)
        return ret;
 }
 
+static blk_qc_t __submit_bio_noacct_mq(struct bio *bio)
+{
+       struct gendisk *disk = bio->bi_disk;
+       struct bio_list bio_list;
+       blk_qc_t ret = BLK_QC_T_NONE;
+
+       bio_list_init(&bio_list);
+       current->bio_list = &bio_list;
+
+       do {
+               WARN_ON_ONCE(bio->bi_disk != disk);
+
+               if (unlikely(bio_queue_enter(bio) != 0))
+                       continue;
+
+               if (!blk_crypto_bio_prep(&bio)) {
+                       blk_queue_exit(disk->queue);
+                       ret = BLK_QC_T_NONE;
+                       continue;
+               }
+
+               ret = blk_mq_submit_bio(bio);
+       } while ((bio = bio_list_pop(&bio_list)));
+
+       current->bio_list = NULL;
+       return ret;
+}
+
 /**
  * submit_bio_noacct - re-submit a bio to the block device layer for I/O
  * @bio:  The bio describing the location in memory and on the device.
@@ -1177,6 +1205,8 @@ blk_qc_t submit_bio_noacct(struct bio *bio)
                return BLK_QC_T_NONE;
        }
 
+       if (!bio->bi_disk->fops->submit_bio)
+               return __submit_bio_noacct_mq(bio);
        return __submit_bio_noacct(bio);
 }
 EXPORT_SYMBOL(submit_bio_noacct);