From 0fbb4d93b38bce1f8235aacfa37e90ad8f011473 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 17 Feb 2022 23:40:32 -0500 Subject: dm: add dm_submit_bio_remap interface Where possible, switch from early bio-based IO accounting (at the time DM clones each incoming bio) to late IO accounting just before each remapped bio is issued to underlying device via submit_bio_noacct(). Allows more precise bio-based IO accounting for DM targets that use their own workqueues to perform additional processing of each bio in conjunction with their DM_MAPIO_SUBMITTED return from their map function. When a target is updated to use dm_submit_bio_remap() they must also set ti->accounts_remapped_io to true. Use xchg() in start_io_acct(), as suggested by Mikulas, to ensure each IO is only started once. The xchg race only happens if __send_duplicate_bios() sends multiple bios -- that case is reflected via tio->is_duplicate_bio. Given the niche nature of this race, it is best to avoid any xchg performance penalty for normal IO. For IO that was never submitted with dm_bio_submit_remap(), but the target completes the clone with bio_endio, accounting is started then ended and pending_io counter decremented. Reviewed-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- include/linux/device-mapper.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index b26fecf6c8e8..7752d14d13f8 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -362,6 +362,12 @@ struct dm_target { * zone append operations using regular writes. */ bool emulate_zone_append:1; + + /* + * Set if the target will submit IO using dm_submit_bio_remap() + * after returning DM_MAPIO_SUBMITTED from its map function. + */ + bool accounts_remapped_io:1; }; void *dm_per_bio_data(struct bio *bio, size_t data_size); @@ -465,6 +471,7 @@ int dm_suspended(struct dm_target *ti); int dm_post_suspending(struct dm_target *ti); int dm_noflush_suspending(struct dm_target *ti); void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors); +void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone, bool from_wq); union map_info *dm_get_rq_mapinfo(struct request *rq); #ifdef CONFIG_BLK_DEV_ZONED -- cgit v1.2.3 From a8b9d116cda047f38ba29ce26df49c57479ffaa2 Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Wed, 26 Jan 2022 05:18:26 -0800 Subject: dm: cleanup double word in comment Remove the second 'a'. Signed-off-by: Tom Rix Signed-off-by: Mike Snitzer --- include/linux/device-mapper.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 7752d14d13f8..70cd9449275a 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -358,7 +358,7 @@ struct dm_target { bool limit_swap_bios:1; /* - * Set if this target implements a a zoned device and needs emulation of + * Set if this target implements a zoned device and needs emulation of * zone append operations using regular writes. */ bool emulate_zone_append:1; -- cgit v1.2.3 From 69fe0f29892077f14b56e2a479b6bcf533209d53 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 4 Mar 2022 21:08:03 -0500 Subject: block: add ->poll_bio to block_device_operations Prepare for supporting IO polling for bio-based driver. Add ->poll_bio callback so that bio-based driver can provide their own logic for polling bio. Also fix ->submit_bio_bio typo in comment block above __submit_bio_noacct. Reviewed-by: Christoph Hellwig Reviewed-by: Jens Axboe Signed-off-by: Ming Lei Signed-off-by: Mike Snitzer --- include/linux/blkdev.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f757f9c2871f..51f1b1ddbed2 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1455,6 +1455,8 @@ enum blk_unique_id { struct block_device_operations { void (*submit_bio)(struct bio *bio); + int (*poll_bio)(struct bio *bio, struct io_comp_batch *iob, + unsigned int flags); int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int); -- cgit v1.2.3 From b7f8dff09827c96032c34a945ee7757e394b5952 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 10 Mar 2022 11:45:58 -0500 Subject: dm: simplify dm_sumbit_bio_remap interface Remove the from_wq argument from dm_sumbit_bio_remap(). Eliminates the need for dm_sumbit_bio_remap() callers to know whether they are calling for a workqueue or from the original dm_submit_bio(). Add map_task to dm_io struct, record the map_task in alloc_io and clear it after all target ->map() calls have completed. Update dm_sumbit_bio_remap to check if 'current' matches io->map_task rather than rely on passed 'from_rq' argument. This change really simplifies the chore of porting each DM target to using dm_sumbit_bio_remap() because there is no longer the risk of programming error by not completely knowing all the different contexts a particular method that calls dm_sumbit_bio_remap() might be used in. Signed-off-by: Mike Snitzer --- include/linux/device-mapper.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 70cd9449275a..901ec191250c 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -471,7 +471,7 @@ int dm_suspended(struct dm_target *ti); int dm_post_suspending(struct dm_target *ti); int dm_noflush_suspending(struct dm_target *ti); void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors); -void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone, bool from_wq); +void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone); union map_info *dm_get_rq_mapinfo(struct request *rq); #ifdef CONFIG_BLK_DEV_ZONED -- cgit v1.2.3