[PATCH 19/20] block: shortcut __submit_bio_noacct for blk-mq drivers

Christoph Hellwig
2020-07-01T09:00:25Z

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>
---
block/blk-core.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index 57b5dc00d44cb1..2ff166f0d24ee3 100644
--- 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);
--
2.26.2