This is a note to let you know that I've just added the patch titled md: revert io stats accounting to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: md-revert-io-stats-accounting.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ad3fc798800fb7ca04c1dfc439dba946818048d8 Mon Sep 17 00:00:00 2001 From: Guoqing Jiang <jgq516@xxxxxxxxx> Date: Tue, 25 May 2021 17:46:16 +0800 Subject: md: revert io stats accounting From: Guoqing Jiang <jgq516@xxxxxxxxx> 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@xxxxxxxxx/T/#t Fixes: 41d2d848e5c0 ("md: improve io stats accounting") Signed-off-by: Guoqing Jiang <jiangguoqing@xxxxxxxxxx> Signed-off-by: Song Liu <song@xxxxxxxxxx> [GM: backport to 5.10-stable] Signed-off-by: Guillaume Morin <guillaume@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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); /* 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(); + return BLK_QC_T_NONE; } @@ -5636,7 +5609,6 @@ static void md_free(struct kobject *ko) bioset_exit(&mddev->bio_set); bioset_exit(&mddev->sync_set); - mempool_exit(&mddev->md_io_pool); kfree(mddev); } @@ -5732,11 +5704,6 @@ static int md_alloc(dev_t dev, char *nam */ mddev->hold_active = UNTIL_STOP; - error = mempool_init_kmalloc_pool(&mddev->md_io_pool, BIO_POOL_SIZE, - sizeof(struct md_io)); - if (error) - goto abort; - error = -ENOMEM; mddev->queue = blk_alloc_queue(NUMA_NO_NODE); if (!mddev->queue) --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -487,7 +487,6 @@ struct mddev { struct bio_set sync_set; /* for sync operations like * metadata and bitmap writes */ - mempool_t md_io_pool; /* Generic flush handling. * The last to finish preflush schedules a worker to submit Patches currently in stable-queue which might be from jgq516@xxxxxxxxx are queue-5.10/md-revert-io-stats-accounting.patch