This makes md do the same thing as dm for write same IO failure. Please
see 7eee4ae(dm: disable WRITE SAME if it fails) for details why we need
this.

Also reported here: https://bugzilla.kernel.org/show_bug.cgi?id=118581

Signed-off-by: Shaohua Li <redacted>
---
 drivers/md/linear.c |  6 +++++-
 drivers/md/md.c     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/md/md.h     |  2 ++
 drivers/md/raid0.c  |  6 +++++-
 4 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 26a73b2..bebc834 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c

@@ -291,7 +291,11 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
 				trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
 						      split, disk_devt(mddev->gendisk),
 						      bio_sector);
-			generic_make_request(split);
+			if (bio_op(split) == REQ_OP_WRITE_SAME)
+				generic_make_request(md_writesame_setup(mddev,
+								split));
+			else
+				generic_make_request(split);
 		}
 	} while (split != bio);
 	return;

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 13020e5..7354f0b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -312,6 +312,51 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
 	return BLK_QC_T_NONE;
 }
 
+struct md_writesame_data {
+	struct bio *orig_bio;
+	struct mddev *mddev;
+	struct bio cloned_bio;
+};
+
+static void md_writesame_endio(struct bio *bio)
+{
+	struct md_writesame_data *data = bio->bi_private;
+
+	if (bio->bi_error == -EREMOTEIO &&
+	    !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
+		data->mddev->queue->limits.max_write_same_sectors = 0;