[dm-devel] [PATCH 14/14] block: add bio_start_io_acct_remapped for the benefit of DM
Mike Snitzer
snitzer at redhat.com
Thu Feb 10 22:38:32 UTC 2022
DM needs the ability to account a clone bio's IO to the original
block_device. So add @orig_bdev argument to bio_start_io_acct_time.
Rename bio_start_io_acct_time to bio_start_io_acct_remapped.
Also, follow bio_end_io_acct and bio_end_io_acct_remapped pattern by
moving bio_start_io_acct to blkdev.h and have it call
bio_start_io_acct_remapped.
Improve DM to no longer need to play games with swizzling a clone
bio's bi_bdev (in dm_submit_bio_remap) and remove DM's
clone_and_start_io_acct() interface.
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
---
block/blk-core.c | 24 ++++++++----------------
drivers/md/dm.c | 41 ++++++++---------------------------------
include/linux/blkdev.h | 16 ++++++++++++++--
3 files changed, 30 insertions(+), 51 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index be8812f5489d..8f23be96c737 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1077,29 +1077,21 @@ static unsigned long __part_start_io_acct(struct block_device *part,
}
/**
- * bio_start_io_acct_time - start I/O accounting for bio based drivers
+ * bio_start_io_acct_remapped - start I/O accounting for bio based drivers
* @bio: bio to start account for
* @start_time: start time that should be passed back to bio_end_io_acct().
- */
-void bio_start_io_acct_time(struct bio *bio, unsigned long start_time)
-{
- __part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
- bio_op(bio), start_time);
-}
-EXPORT_SYMBOL_GPL(bio_start_io_acct_time);
-
-/**
- * bio_start_io_acct - start I/O accounting for bio based drivers
- * @bio: bio to start account for
+ * @orig_bdev: block device that I/O must be accounted to.
*
* Returns the start time that should be passed back to bio_end_io_acct().
*/
-unsigned long bio_start_io_acct(struct bio *bio)
+unsigned long bio_start_io_acct_remapped(struct bio *bio,
+ unsigned long start_time,
+ struct block_device *orig_bdev)
{
- return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
- bio_op(bio), jiffies);
+ return __part_start_io_acct(orig_bdev, bio_sectors(bio),
+ bio_op(bio), start_time);
}
-EXPORT_SYMBOL_GPL(bio_start_io_acct);
+EXPORT_SYMBOL_GPL(bio_start_io_acct_remapped);
unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
unsigned int op)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 329f0be64523..e020f505e243 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -485,35 +485,19 @@ u64 dm_start_time_ns_from_clone(struct bio *bio)
}
EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
-static void __start_io_acct(struct dm_io *io, struct bio *bio)
-{
- bio_start_io_acct_time(bio, io->start_time);
- if (unlikely(dm_stats_used(&io->md->stats)))
- dm_stats_account_io(&io->md->stats, bio_data_dir(bio),
- bio->bi_iter.bi_sector, bio_sectors(bio),
- false, 0, &io->stats_aux);
-}
-
static void start_io_acct(struct dm_io *io, struct bio *bio)
{
/* Ensure IO accounting is only ever started once */
if (xchg(&io->was_accounted, 1) == 1)
return;
- __start_io_acct(io, bio);
-}
+ bio_start_io_acct_remapped(bio, io->start_time,
+ io->orig_bio->bi_bdev);
-static void clone_and_start_io_acct(struct dm_io *io, struct bio *bio)
-{
- struct bio io_acct_clone;
-
- /* Ensure IO accounting is only ever started once */
- if (xchg(&io->was_accounted, 1) == 1)
- return;
-
- bio_init_clone(io->orig_bio->bi_bdev,
- &io_acct_clone, bio, GFP_NOIO);
- __start_io_acct(io, &io_acct_clone);
+ if (unlikely(dm_stats_used(&io->md->stats)))
+ dm_stats_account_io(&io->md->stats, bio_data_dir(bio),
+ bio->bi_iter.bi_sector, bio_sectors(bio),
+ false, 0, &io->stats_aux);
}
static void end_io_acct(struct mapped_device *md, struct bio *bio,
@@ -1137,7 +1121,6 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_io *io = tio->io;
- struct block_device *clone_bdev = clone->bi_bdev;
/* establish bio that will get submitted */
if (!tgt_clone)
@@ -1151,9 +1134,7 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
* io->orig_bio so there is no IO imbalance in
* end_io_acct().
*/
- clone->bi_bdev = io->orig_bio->bi_bdev;
start_io_acct(io, clone);
- clone->bi_bdev = clone_bdev;
trace_block_bio_remap(tgt_clone, bio_dev(io->orig_bio),
tio->old_sector);
@@ -1213,14 +1194,8 @@ static void __map_bio(struct bio *clone)
switch (r) {
case DM_MAPIO_SUBMITTED:
/* target has assumed ownership of this io */
- if (!ti->accounts_remapped_io) {
- /*
- * Any split isn't reflected in io->orig_bio yet. And bio
- * cannot be modified because target is submitting it.
- * Clone bio and account IO to DM device.
- */
- clone_and_start_io_acct(io, clone);
- }
+ if (!ti->accounts_remapped_io)
+ start_io_acct(io, clone);
break;
case DM_MAPIO_REMAPPED:
/* the bio has been remapped so dispatch it */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3bfc75a2a450..31d055d4a17e 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1512,11 +1512,23 @@ unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
void disk_end_io_acct(struct gendisk *disk, unsigned int op,
unsigned long start_time);
-void bio_start_io_acct_time(struct bio *bio, unsigned long start_time);
-unsigned long bio_start_io_acct(struct bio *bio);
+unsigned long bio_start_io_acct_remapped(struct bio *bio,
+ unsigned long start_time,
+ struct block_device *orig_bdev);
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
struct block_device *orig_bdev);
+/**
+ * bio_start_io_acct - start I/O accounting for bio based drivers
+ * @bio: bio to start account for
+ *
+ * Returns the start time that should be passed back to bio_end_io_acct().
+ */
+static inline unsigned long bio_start_io_acct(struct bio *bio)
+{
+ return bio_start_io_acct_remapped(bio, jiffies, bio->bi_bdev);
+}
+
/**
* bio_end_io_acct - end I/O accounting for bio based drivers
* @bio: bio to end account for
--
2.15.0
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