On Wed, Jan 26, 2022 at 01:37:12PM +0100, Jack Wang wrote:
Greg Kroah-Hartman gregkh@linuxfoundation.org 于2022年1月26日周三 12:42写道：
On Wed, Jan 26, 2022 at 11:09:46AM +0100, Jack Wang wrote:
Hi,
Greg Kroah-Hartman gregkh@linuxfoundation.org 于2022年1月14日周五 19:57写道：
From: Guoqing Jiang jgq516@gmail.com
commit ad3fc798800fb7ca04c1dfc439dba946818048d8 upstream.
The commit 41d2d848e5c0 ("md: improve io stats accounting") could cause double fault problem per the report [1], and also it is not correct to change ->bi_end_io if md don't own it, so let's revert it.
And io stats accounting will be replemented in later commits.
[1]. https://lore.kernel.org/linux-raid/3bf04253-3fad-434a-63a7-20214e38cf26@gmai...
Fixes: 41d2d848e5c0 ("md: improve io stats accounting") Signed-off-by: Guoqing Jiang jiangguoqing@kylinos.cn Signed-off-by: Song Liu song@kernel.org [GM: backport to 5.10-stable] Signed-off-by: Guillaume Morin guillaume@morinfr.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/md/md.c | 57 +++++++++++--------------------------------------------- drivers/md/md.h | 1 2 files changed, 12 insertions(+), 46 deletions(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -459,34 +459,12 @@ check_suspended: } EXPORT_SYMBOL(md_handle_request);
-struct md_io {
struct mddev *mddev;bio_end_io_t *orig_bi_end_io;void *orig_bi_private;unsigned long start_time;struct hd_struct *part;-};
-static void md_end_io(struct bio *bio) -{
struct md_io *md_io = bio->bi_private;struct mddev *mddev = md_io->mddev;part_end_io_acct(md_io->part, bio, md_io->start_time);bio->bi_end_io = md_io->orig_bi_end_io;bio->bi_private = md_io->orig_bi_private;mempool_free(md_io, &mddev->md_io_pool);if (bio->bi_end_io)bio->bi_end_io(bio);-}
static blk_qc_t md_submit_bio(struct bio *bio) { const int rw = bio_data_dir(bio);
const int sgrp = op_stat_group(bio_op(bio)); struct mddev *mddev = bio->bi_disk->private_data;unsigned int sectors; if (mddev == NULL || mddev->pers == NULL) { bio_io_error(bio);@@ -507,26 +485,21 @@ static blk_qc_t md_submit_bio(struct bio return BLK_QC_T_NONE; }
if (bio->bi_end_io != md_end_io) {struct md_io *md_io;md_io = mempool_alloc(&mddev->md_io_pool, GFP_NOIO);md_io->mddev = mddev;md_io->orig_bi_end_io = bio->bi_end_io;md_io->orig_bi_private = bio->bi_private;bio->bi_end_io = md_end_io;bio->bi_private = md_io;md_io->start_time = part_start_io_acct(mddev->gendisk,&md_io->part, bio);}
/** save the sectors now since our bio can* go away inside make_request*/sectors = bio_sectors(bio);This code snip is not inside the original patch, and it's not in latest upstream too.
/* bio could be mergeable after passing to underlayer */ bio->bi_opf &= ~REQ_NOMERGE; md_handle_request(mddev, bio);
part_stat_lock();part_stat_inc(&mddev->gendisk->part0, ios[sgrp]);part_stat_add(&mddev->gendisk->part0, sectors[sgrp], sectors);part_stat_unlock();same here, this code snip is not inside the original patch, and it's not in latest upstream too.
Is it a problem?
Not sure, might cause some confusion regarding io stats.
I think would be good keep it as the upstream version.
Can you send a revert of this commit (it is in 5.10.92), and a backport of the correct fix?
sure, I just sent an incremental fix for the backport itself. is it ok?
That works, I'll queue it up after this next round of releases, thanks!
greg k-h