md: support REQ_OP_WRITE_ZEROES

Copy & paste from the REQ_OP_WRITE_SAME code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/md/linear.c

@@ -293,6 +293,7 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
 						      split, disk_devt(mddev->gendisk),
 						      bio_sector);
 			mddev_check_writesame(mddev, split);
+			mddev_check_write_zeroes(mddev, split);
 			generic_make_request(split);
 		}
 	} while (split != bio);

drivers/md/md.h

@@ -709,4 +709,11 @@ static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
 	    !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
 		mddev->queue->limits.max_write_same_sectors = 0;
 }
+
+static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio)
+{
+	if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
+	    !bdev_get_queue(bio->bi_bdev)->limits.max_write_zeroes_sectors)
+		mddev->queue->limits.max_write_zeroes_sectors = 0;
+}
 #endif /* _MD_MD_H */

drivers/md/multipath.c

@@ -139,6 +139,7 @@ static void multipath_make_request(struct mddev *mddev, struct bio * bio)
 	mp_bh->bio.bi_end_io = multipath_end_request;
 	mp_bh->bio.bi_private = mp_bh;
 	mddev_check_writesame(mddev, &mp_bh->bio);
+	mddev_check_write_zeroes(mddev, &mp_bh->bio);
 	generic_make_request(&mp_bh->bio);
 	return;
 }

drivers/md/raid0.c

@@ -383,6 +383,7 @@ static int raid0_run(struct mddev *mddev)
 
 		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
 		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
+		blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
 		blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
 
 		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
@@ -504,6 +505,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
 						      split, disk_devt(mddev->gendisk),
 						      bio_sector);
 			mddev_check_writesame(mddev, split);
+			mddev_check_write_zeroes(mddev, split);
 			generic_make_request(split);
 		}
 	} while (split != bio);

drivers/md/raid1.c

@@ -3177,8 +3177,10 @@ static int raid1_run(struct mddev *mddev)
 	if (IS_ERR(conf))
 		return PTR_ERR(conf);
 
-	if (mddev->queue)
+	if (mddev->queue) {
 		blk_queue_max_write_same_sectors(mddev->queue, 0);
+		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
+	}
 
 	rdev_for_each(rdev, mddev) {
 		if (!mddev->gendisk)

drivers/md/raid10.c

@@ -3749,6 +3749,7 @@ static int raid10_run(struct mddev *mddev)
 		blk_queue_max_discard_sectors(mddev->queue,
 					      mddev->chunk_sectors);
 		blk_queue_max_write_same_sectors(mddev->queue, 0);
+		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
 		blk_queue_io_min(mddev->queue, chunk_size);
 		if (conf->geo.raid_disks % conf->geo.near_copies)
 			blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);

drivers/md/raid5.c

@@ -7270,6 +7270,7 @@ static int raid5_run(struct mddev *mddev)
 		mddev->queue->limits.discard_zeroes_data = 0;
 
 		blk_queue_max_write_same_sectors(mddev->queue, 0);
+		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
 
 		rdev_for_each(rdev, mddev) {
 			disk_stack_limits(mddev->gendisk, rdev->bdev,