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From: Guoqing Jiang <jgq516@gmail.com>
To: song@kernel.org
Cc: linux-raid@vger.kernel.org, artur.paszkiewicz@intel.com
Subject: [PATCH V2 1/7] md: revert io stats accounting
Date: Fri, 21 May 2021 08:55:15 +0800	[thread overview]
Message-ID: <20210521005521.713106-2-jiangguoqing@kylinos.cn> (raw)
In-Reply-To: <20210521005521.713106-1-jiangguoqing@kylinos.cn>

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@gmail.com/T/#t

Fixes: 41d2d848e5c0 ("md: improve io stats accounting")
Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
---
 drivers/md/md.c | 45 ---------------------------------------------
 drivers/md/md.h |  1 -
 2 files changed, 46 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 49f897fbb89b..7ba00e4c862d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -441,30 +441,6 @@ void md_handle_request(struct mddev *mddev, struct bio *bio)
 }
 EXPORT_SYMBOL(md_handle_request);
 
-struct md_io {
-	struct mddev *mddev;
-	bio_end_io_t *orig_bi_end_io;
-	void *orig_bi_private;
-	struct block_device *orig_bi_bdev;
-	unsigned long start_time;
-};
-
-static void md_end_io(struct bio *bio)
-{
-	struct md_io *md_io = bio->bi_private;
-	struct mddev *mddev = md_io->mddev;
-
-	bio_end_io_acct_remapped(bio, md_io->start_time, md_io->orig_bi_bdev);
-
-	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);
@@ -489,21 +465,6 @@ static blk_qc_t md_submit_bio(struct bio *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;
-		md_io->orig_bi_bdev = bio->bi_bdev;
-
-		bio->bi_end_io = md_end_io;
-		bio->bi_private = md_io;
-
-		md_io->start_time = bio_start_io_acct(bio);
-	}
-
 	/* bio could be mergeable after passing to underlayer */
 	bio->bi_opf &= ~REQ_NOMERGE;
 
@@ -5608,7 +5569,6 @@ 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);
 }
 
@@ -5705,11 +5665,6 @@ static int md_alloc(dev_t dev, char *name)
 		 */
 		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)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index fb7eab58cfd5..4da240ffe2c5 100644
--- 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
-- 
2.25.1


  reply	other threads:[~2021-05-21  0:56 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21  0:55 [PATCH V2 0/7] md: io stats accounting Guoqing Jiang
2021-05-21  0:55 ` Guoqing Jiang [this message]
2021-05-21  0:55 ` [PATCH V2 2/7] md: add accounting_bio for raid0 and raid5 Guoqing Jiang
2021-05-24  5:48   ` Song Liu
2021-05-24  8:45   ` Christoph Hellwig
2021-05-21  0:55 ` [PATCH V2 3/7] md: the latest try for improve io stats accounting Guoqing Jiang
2021-05-21  7:32   ` Artur Paszkiewicz
2021-05-21  7:43     ` Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 4/7] md/raid1: rename print_msg with r1bio_existed Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 5/7] md/raid1: enable io accounting Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 6/7] md/raid10: " Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 7/7] md: mark some personalities as deprecated Guoqing Jiang
2021-05-21  8:00 ` [UPDATE PATCH V2 3/7] md: the latest try for improve io stats accounting Guoqing Jiang
2021-05-24  5:49   ` Song Liu
2021-05-24  6:04 ` [PATCH V2 0/7] md: " Song Liu
2021-05-27 14:09   ` Paweł Wiejacha

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