The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e45c47d1f94e0cc7b6b079fdb4bcce2995e2adc4 Mon Sep 17 00:00:00 2001 From: Mike Snitzer snitzer@redhat.com Date: Fri, 28 Jan 2022 10:58:39 -0500 Subject: [PATCH] block: add bio_start_io_acct_time() to control start_time

bio_start_io_acct_time() interface is like bio_start_io_acct() that allows start_time to be passed in. This gives drivers the ability to defer starting accounting until after IO is issued (but possibily not entirely due to bio splitting).

Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Mike Snitzer snitzer@redhat.com Link: https://lore.kernel.org/r/20220128155841.39644-2-snitzer@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/block/blk-core.c b/block/blk-core.c index 97f8bc8d3a79..d93e3bb9a769 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1061,20 +1061,32 @@ again: }

static unsigned long __part_start_io_acct(struct block_device *part, - unsigned int sectors, unsigned int op) + unsigned int sectors, unsigned int op, + unsigned long start_time) { const int sgrp = op_stat_group(op); - unsigned long now = READ_ONCE(jiffies);

part_stat_lock(); - update_io_ticks(part, now, false); + update_io_ticks(part, start_time, false); part_stat_inc(part, ios[sgrp]); part_stat_add(part, sectors[sgrp], sectors); part_stat_local_inc(part, in_flight[op_is_write(op)]); part_stat_unlock();

- return now; + return start_time; +} + +/** + * bio_start_io_acct_time - 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 @@ -1084,14 +1096,15 @@ static unsigned long __part_start_io_acct(struct block_device *part, */ unsigned long bio_start_io_acct(struct bio *bio) { - return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio), bio_op(bio)); + return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio), + bio_op(bio), jiffies); } EXPORT_SYMBOL_GPL(bio_start_io_acct);

unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors, unsigned int op) { - return __part_start_io_acct(disk->part0, sectors, op); + return __part_start_io_acct(disk->part0, sectors, op, jiffies); } EXPORT_SYMBOL(disk_start_io_acct);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9c95df26fc26..f35aea98bc35 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1258,6 +1258,7 @@ 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); void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, struct block_device *orig_bdev);