md: revert io stats accounting

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>
Signed-off-by: Song Liu <song@kernel.org>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 49f897fbb89ba3f9dd75fe76c0e63d604ba12ef1..7ba00e4c862d7bc7d3ffa02b8e590f8b170e248d 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -441,30 +441,6 @@ 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;
-       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 fb7eab58cfd517b3f52e7de0898104df2a71b2a0..4da240ffe2c5ecf4d4d7ae96b5f257c175829540 100644 (file)
--- 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