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

Christoph Hellwig
2020-06-29T19:41:38Z

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 | 50 +++++++++++++++++++++++++++++++++---------------
1 file changed, 35 insertions(+), 15 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index b82f48c86e6f7a..46e3c0a37cc377 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1071,20 +1071,6 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
return false;
}

-static blk_qc_t do_make_request(struct bio *bio)
-{
- struct gendisk *disk = bio->bi_disk;
- blk_qc_t ret = BLK_QC_T_NONE;
-
- if (blk_crypto_bio_prep(&bio)) {
- if (!disk->fops->submit_bio)
- return blk_mq_submit_bio(bio);
- ret = disk->fops->submit_bio(bio);
- }
- blk_queue_exit(disk->queue);
- return ret;
-}
-
/*
* The loop in this function may be a bit non-obvious, and so deserves some
* explanation:
@@ -1127,7 +1113,11 @@ static blk_qc_t __submit_bio_noacct(struct bio *bio)
bio_list_on_stack[1] = bio_list_on_stack[0];
bio_list_init(&bio_list_on_stack[0]);

- ret = do_make_request(bio);
+ if (blk_crypto_bio_prep(&bio))
+ ret = bio->bi_disk->fops->submit_bio(bio);
+ else
+ ret = BLK_QC_T_NONE;
+ blk_queue_exit(q);

/*
* Sort new bios into those for a lower level and those for the
@@ -1153,6 +1143,34 @@ 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.
@@ -1182,6 +1200,8 @@ blk_qc_t submit_bio_noacct(struct bio *bio)
return BLK_QC_T_NONE;
}

+ if (bio->bi_disk->queue->mq_ops)
+ return __submit_bio_noacct_mq(bio);
return __submit_bio_noacct(bio);
}
EXPORT_SYMBOL(submit_bio_noacct);
--
2.26.2