diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2010-09-08 20:07:01 +0400 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2010-09-10 14:35:38 +0400 |
| commit | b372d360df6deaf79a58a02fa0cc0d7e0aa3e92f (patch) | |
| tree | e103bc03bae17f7a995ba44825aefd5fc5fdba66 | |
| parent | 05447420f99c1c44063c7f00054667c022cc1365 (diff) | |
| download | linux-b372d360df6deaf79a58a02fa0cc0d7e0aa3e92f.tar.xz | |
dm: convey that all flushes are processed as empty
Rename __clone_and_map_flush to __clone_and_map_empty_flush for added
clarity.
Simplify logic associated with REQ_FLUSH conditionals.
Introduce a BUG_ON() and add a few more helpful comments to the code
so that it is clear that all flushes are empty.
Cleanup __split_and_process_bio() so that an empty flush isn't processed
by a 'sector_count' focused while loop.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| -rw-r--r-- | drivers/md/dm.c | 34 |
1 files changed, 15 insertions, 19 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index cd2f7e77b625..f934e9878436 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -621,16 +621,17 @@ static void dec_pending(struct dm_io *io, int error) if (io_error == DM_ENDIO_REQUEUE) return; - if (!(bio->bi_rw & REQ_FLUSH) || !bio->bi_size) { - trace_block_bio_complete(md->queue, bio); - bio_endio(bio, io_error); - } else { + if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) { /* * Preflush done for flush with data, reissue * without REQ_FLUSH. */ bio->bi_rw &= ~REQ_FLUSH; queue_io(md, bio); + } else { + /* done with normal IO or empty flush */ + trace_block_bio_complete(md->queue, bio); + bio_endio(bio, io_error); } } } @@ -1132,16 +1133,15 @@ static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti, __issue_target_request(ci, ti, request_nr, len); } -static int __clone_and_map_flush(struct clone_info *ci) +static int __clone_and_map_empty_flush(struct clone_info *ci) { unsigned target_nr = 0; struct dm_target *ti; + BUG_ON(bio_has_data(ci->bio)); while ((ti = dm_table_get_target(ci->map, target_nr++))) __issue_target_requests(ci, ti, ti->num_flush_requests, 0); - ci->sector_count = 0; - return 0; } @@ -1282,7 +1282,6 @@ static int __clone_and_map(struct clone_info *ci) */ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) { - bool is_flush = bio->bi_rw & REQ_FLUSH; struct clone_info ci; int error = 0; @@ -1302,20 +1301,17 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) ci.sector = bio->bi_sector; ci.idx = bio->bi_idx; - if (!is_flush) { + start_io_acct(ci.io); + if (bio->bi_rw & REQ_FLUSH) { + ci.bio = &ci.md->flush_bio; + ci.sector_count = 0; + error = __clone_and_map_empty_flush(&ci); + /* dec_pending submits any data associated with flush */ + } else { ci.bio = bio; ci.sector_count = bio_sectors(bio); - } else { - ci.bio = &ci.md->flush_bio; - ci.sector_count = 1; - } - - start_io_acct(ci.io); - while (ci.sector_count && !error) { - if (!is_flush) + while (ci.sector_count && !error) error = __clone_and_map(&ci); - else - error = __clone_and_map_flush(&ci); } /* drop the extra reference count */ |