[PATCH 64/78] dm: simplify flush_bio initialization in __send_empty_flush

Christoph Hellwig
2020-11-16T15:12:29Z

We don't really need the struct block_device to initialize a bio. So
switch from using bio_set_dev to manually setting up bi_disk (bi_partno
will always be zero and has been cleared by bio_init already).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/md/dm.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 54739f1b579bc8..6d7eb72d41f9ea 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1422,18 +1422,12 @@ static int __send_empty_flush(struct clone_info *ci)
*/
bio_init(&flush_bio, NULL, 0);
flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
+ flush_bio.bi_disk = ci->io->md->disk;
+ bio_associate_blkg(&flush_bio);
+
ci->bio = &flush_bio;
ci->sector_count = 0;

- /*
- * Empty flush uses a statically initialized bio, as the base for
- * cloning. However, blkg association requires that a bdev is
- * associated with a gendisk, which doesn't happen until the bdev is
- * opened. So, blkg association is done at issue time of the flush
- * rather than when the device is created in alloc_dev().
- */
- bio_set_dev(ci->bio, ci->io->md->bdev);
-
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);