Re: [PATCH v4 08/11] block: kill merge_bvec_fn() completely

From: NeilBrown
Date: Mon May 25 2015 - 01:49:49 EST


On Fri, 22 May 2015 11:18:40 -0700 Ming Lin <mlin@xxxxxxxxxx> wrote:

> From: Kent Overstreet <kent.overstreet@xxxxxxxxx>
>
> As generic_make_request() is now able to handle arbitrarily sized bios,
> it's no longer necessary for each individual block driver to define its
> own ->merge_bvec_fn() callback. Remove every invocation completely.
>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Lars Ellenberg <drbd-dev@xxxxxxxxxxxxxxxx>
> Cc: drbd-user@xxxxxxxxxxxxxxxx
> Cc: Jiri Kosina <jkosina@xxxxxxx>
> Cc: Yehuda Sadeh <yehuda@xxxxxxxxxxx>
> Cc: Sage Weil <sage@xxxxxxxxxxx>
> Cc: Alex Elder <elder@xxxxxxxxxx>
> Cc: ceph-devel@xxxxxxxxxxxxxxx
> Cc: Alasdair Kergon <agk@xxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: dm-devel@xxxxxxxxxx
> Cc: Neil Brown <neilb@xxxxxxx>
> Cc: linux-raid@xxxxxxxxxxxxxxx
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> [dpark: also remove ->merge_bvec_fn() in dm-thin as well as
> dm-era-target, and resolve merge conflicts]
> Signed-off-by: Dongsu Park <dpark@xxxxxxxxxx>
> Signed-off-by: Ming Lin <mlin@xxxxxxxxxx>

Acked-by: NeilBrown <neilb@xxxxxxx> (for the 'md' bits)

Very happy to see this happening!

Thanks,
NeilBrown


> ---
> block/blk-merge.c | 17 +-----
> block/blk-settings.c | 22 --------
> drivers/block/drbd/drbd_int.h | 1 -
> drivers/block/drbd/drbd_main.c | 1 -
> drivers/block/drbd/drbd_req.c | 35 ------------
> drivers/block/pktcdvd.c | 21 -------
> drivers/block/rbd.c | 47 ----------------
> drivers/md/dm-cache-target.c | 21 -------
> drivers/md/dm-crypt.c | 16 ------
> drivers/md/dm-era-target.c | 15 -----
> drivers/md/dm-flakey.c | 16 ------
> drivers/md/dm-linear.c | 16 ------
> drivers/md/dm-log-writes.c | 16 ------
> drivers/md/dm-snap.c | 15 -----
> drivers/md/dm-stripe.c | 21 -------
> drivers/md/dm-table.c | 8 ---
> drivers/md/dm-thin.c | 31 -----------
> drivers/md/dm-verity.c | 16 ------
> drivers/md/dm.c | 120 +---------------------------------------
> drivers/md/dm.h | 2 -
> drivers/md/linear.c | 43 ---------------
> drivers/md/md.c | 26 ---------
> drivers/md/md.h | 12 ----
> drivers/md/multipath.c | 21 -------
> drivers/md/raid0.c | 56 -------------------
> drivers/md/raid0.h | 2 -
> drivers/md/raid1.c | 58 +-------------------
> drivers/md/raid10.c | 121 +----------------------------------------
> drivers/md/raid5.c | 32 -----------
> include/linux/blkdev.h | 10 ----
> include/linux/device-mapper.h | 4 --
> 31 files changed, 9 insertions(+), 833 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index dc14255..25cafb8 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -69,24 +69,13 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
> struct bio *split;
> struct bio_vec bv, bvprv;
> struct bvec_iter iter;
> - unsigned seg_size = 0, nsegs = 0;
> + unsigned seg_size = 0, nsegs = 0, sectors = 0;
> int prev = 0;
>
> - struct bvec_merge_data bvm = {
> - .bi_bdev = bio->bi_bdev,
> - .bi_sector = bio->bi_iter.bi_sector,
> - .bi_size = 0,
> - .bi_rw = bio->bi_rw,
> - };
> -
> bio_for_each_segment(bv, bio, iter) {
> - if (q->merge_bvec_fn &&
> - q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
> - goto split;
> -
> - bvm.bi_size += bv.bv_len;
> + sectors += bv.bv_len >> 9;
>
> - if (bvm.bi_size >> 9 > queue_max_sectors(q))
> + if (sectors > queue_max_sectors(q))
> goto split;
>
> /*
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 12600bf..e90d477 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -53,28 +53,6 @@ void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
> }
> EXPORT_SYMBOL(blk_queue_unprep_rq);
>
> -/**
> - * blk_queue_merge_bvec - set a merge_bvec function for queue
> - * @q: queue
> - * @mbfn: merge_bvec_fn
> - *
> - * Usually queues have static limitations on the max sectors or segments that
> - * we can put in a request. Stacking drivers may have some settings that
> - * are dynamic, and thus we have to query the queue whether it is ok to
> - * add a new bio_vec to a bio at a given offset or not. If the block device
> - * has such limitations, it needs to register a merge_bvec_fn to control
> - * the size of bio's sent to it. Note that a block device *must* allow a
> - * single page to be added to an empty bio. The block device driver may want
> - * to use the bio_split() function to deal with these bio's. By default
> - * no merge_bvec_fn is defined for a queue, and only the fixed limits are
> - * honored.
> - */
> -void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
> -{
> - q->merge_bvec_fn = mbfn;
> -}
> -EXPORT_SYMBOL(blk_queue_merge_bvec);
> -
> void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
> {
> q->softirq_done_fn = fn;
> diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
> index b905e98..63ce2b0 100644
> --- a/drivers/block/drbd/drbd_int.h
> +++ b/drivers/block/drbd/drbd_int.h
> @@ -1449,7 +1449,6 @@ extern void do_submit(struct work_struct *ws);
> extern void __drbd_make_request(struct drbd_device *, struct bio *, unsigned long);
> extern void drbd_make_request(struct request_queue *q, struct bio *bio);
> extern int drbd_read_remote(struct drbd_device *device, struct drbd_request *req);
> -extern int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec);
> extern int is_valid_ar_handle(struct drbd_request *, sector_t);
>
>
> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> index 81fde9e..771e68c 100644
> --- a/drivers/block/drbd/drbd_main.c
> +++ b/drivers/block/drbd/drbd_main.c
> @@ -2774,7 +2774,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
> This triggers a max_bio_size message upon first attach or connect */
> blk_queue_max_hw_sectors(q, DRBD_MAX_BIO_SIZE_SAFE >> 8);
> blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
> - blk_queue_merge_bvec(q, drbd_merge_bvec);
> q->queue_lock = &resource->req_lock;
>
> device->md_io.page = alloc_page(GFP_KERNEL);
> diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
> index a6265bc..7523f00 100644
> --- a/drivers/block/drbd/drbd_req.c
> +++ b/drivers/block/drbd/drbd_req.c
> @@ -1510,41 +1510,6 @@ void drbd_make_request(struct request_queue *q, struct bio *bio)
> __drbd_make_request(device, bio, start_jif);
> }
>
> -/* This is called by bio_add_page().
> - *
> - * q->max_hw_sectors and other global limits are already enforced there.
> - *
> - * We need to call down to our lower level device,
> - * in case it has special restrictions.
> - *
> - * We also may need to enforce configured max-bio-bvecs limits.
> - *
> - * As long as the BIO is empty we have to allow at least one bvec,
> - * regardless of size and offset, so no need to ask lower levels.
> - */
> -int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
> -{
> - struct drbd_device *device = (struct drbd_device *) q->queuedata;
> - unsigned int bio_size = bvm->bi_size;
> - int limit = DRBD_MAX_BIO_SIZE;
> - int backing_limit;
> -
> - if (bio_size && get_ldev(device)) {
> - unsigned int max_hw_sectors = queue_max_hw_sectors(q);
> - struct request_queue * const b =
> - device->ldev->backing_bdev->bd_disk->queue;
> - if (b->merge_bvec_fn) {
> - bvm->bi_bdev = device->ldev->backing_bdev;
> - backing_limit = b->merge_bvec_fn(b, bvm, bvec);
> - limit = min(limit, backing_limit);
> - }
> - put_ldev(device);
> - if ((limit >> 9) > max_hw_sectors)
> - limit = max_hw_sectors << 9;
> - }
> - return limit;
> -}
> -
> void request_timer_fn(unsigned long data)
> {
> struct drbd_device *device = (struct drbd_device *) data;
> diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
> index ea10bd9..85eac23 100644
> --- a/drivers/block/pktcdvd.c
> +++ b/drivers/block/pktcdvd.c
> @@ -2505,26 +2505,6 @@ end_io:
>
>
>
> -static int pkt_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
> - struct bio_vec *bvec)
> -{
> - struct pktcdvd_device *pd = q->queuedata;
> - sector_t zone = get_zone(bmd->bi_sector, pd);
> - int used = ((bmd->bi_sector - zone) << 9) + bmd->bi_size;
> - int remaining = (pd->settings.size << 9) - used;
> - int remaining2;
> -
> - /*
> - * A bio <= PAGE_SIZE must be allowed. If it crosses a packet
> - * boundary, pkt_make_request() will split the bio.
> - */
> - remaining2 = PAGE_SIZE - bmd->bi_size;
> - remaining = max(remaining, remaining2);
> -
> - BUG_ON(remaining < 0);
> - return remaining;
> -}
> -
> static void pkt_init_queue(struct pktcdvd_device *pd)
> {
> struct request_queue *q = pd->disk->queue;
> @@ -2532,7 +2512,6 @@ static void pkt_init_queue(struct pktcdvd_device *pd)
> blk_queue_make_request(q, pkt_make_request);
> blk_queue_logical_block_size(q, CD_FRAMESIZE);
> blk_queue_max_hw_sectors(q, PACKET_MAX_SECTORS);
> - blk_queue_merge_bvec(q, pkt_merge_bvec);
> q->queuedata = pd;
> }
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index ec6c5c6..f50edb3 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -3440,52 +3440,6 @@ static int rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
> return BLK_MQ_RQ_QUEUE_OK;
> }
>
> -/*
> - * a queue callback. Makes sure that we don't create a bio that spans across
> - * multiple osd objects. One exception would be with a single page bios,
> - * which we handle later at bio_chain_clone_range()
> - */
> -static int rbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
> - struct bio_vec *bvec)
> -{
> - struct rbd_device *rbd_dev = q->queuedata;
> - sector_t sector_offset;
> - sector_t sectors_per_obj;
> - sector_t obj_sector_offset;
> - int ret;
> -
> - /*
> - * Find how far into its rbd object the partition-relative
> - * bio start sector is to offset relative to the enclosing
> - * device.
> - */
> - sector_offset = get_start_sect(bmd->bi_bdev) + bmd->bi_sector;
> - sectors_per_obj = 1 << (rbd_dev->header.obj_order - SECTOR_SHIFT);
> - obj_sector_offset = sector_offset & (sectors_per_obj - 1);
> -
> - /*
> - * Compute the number of bytes from that offset to the end
> - * of the object. Account for what's already used by the bio.
> - */
> - ret = (int) (sectors_per_obj - obj_sector_offset) << SECTOR_SHIFT;
> - if (ret > bmd->bi_size)
> - ret -= bmd->bi_size;
> - else
> - ret = 0;
> -
> - /*
> - * Don't send back more than was asked for. And if the bio
> - * was empty, let the whole thing through because: "Note
> - * that a block device *must* allow a single page to be
> - * added to an empty bio."
> - */
> - rbd_assert(bvec->bv_len <= PAGE_SIZE);
> - if (ret > (int) bvec->bv_len || !bmd->bi_size)
> - ret = (int) bvec->bv_len;
> -
> - return ret;
> -}
> -
> static void rbd_free_disk(struct rbd_device *rbd_dev)
> {
> struct gendisk *disk = rbd_dev->disk;
> @@ -3784,7 +3738,6 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
> q->limits.max_discard_sectors = segment_size / SECTOR_SIZE;
> q->limits.discard_zeroes_data = 1;
>
> - blk_queue_merge_bvec(q, rbd_merge_bvec);
> disk->queue = q;
>
> q->queuedata = rbd_dev;
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index 7755af3..2e47e35 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -3289,26 +3289,6 @@ static int cache_iterate_devices(struct dm_target *ti,
> return r;
> }
>
> -/*
> - * We assume I/O is going to the origin (which is the volume
> - * more likely to have restrictions e.g. by being striped).
> - * (Looking up the exact location of the data would be expensive
> - * and could always be out of date by the time the bio is submitted.)
> - */
> -static int cache_bvec_merge(struct dm_target *ti,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct cache *cache = ti->private;
> - struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = cache->origin_dev->bdev;
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
> {
> /*
> @@ -3352,7 +3332,6 @@ static struct target_type cache_target = {
> .status = cache_status,
> .message = cache_message,
> .iterate_devices = cache_iterate_devices,
> - .merge = cache_bvec_merge,
> .io_hints = cache_io_hints,
> };
>
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index 5503e43..d13f330 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -2017,21 +2017,6 @@ error:
> return -EINVAL;
> }
>
> -static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct crypt_config *cc = ti->private;
> - struct request_queue *q = bdev_get_queue(cc->dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = cc->dev->bdev;
> - bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int crypt_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -2052,7 +2037,6 @@ static struct target_type crypt_target = {
> .preresume = crypt_preresume,
> .resume = crypt_resume,
> .message = crypt_message,
> - .merge = crypt_merge,
> .iterate_devices = crypt_iterate_devices,
> };
>
> diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
> index ad913cd..0119ebf 100644
> --- a/drivers/md/dm-era-target.c
> +++ b/drivers/md/dm-era-target.c
> @@ -1673,20 +1673,6 @@ static int era_iterate_devices(struct dm_target *ti,
> return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
> }
>
> -static int era_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct era *era = ti->private;
> - struct request_queue *q = bdev_get_queue(era->origin_dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = era->origin_dev->bdev;
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
> {
> struct era *era = ti->private;
> @@ -1717,7 +1703,6 @@ static struct target_type era_target = {
> .status = era_status,
> .message = era_message,
> .iterate_devices = era_iterate_devices,
> - .merge = era_merge,
> .io_hints = era_io_hints
> };
>
> diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
> index b257e46..d955b3e 100644
> --- a/drivers/md/dm-flakey.c
> +++ b/drivers/md/dm-flakey.c
> @@ -387,21 +387,6 @@ static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long ar
> return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
> }
>
> -static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct flakey_c *fc = ti->private;
> - struct request_queue *q = bdev_get_queue(fc->dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = fc->dev->bdev;
> - bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
> {
> struct flakey_c *fc = ti->private;
> @@ -419,7 +404,6 @@ static struct target_type flakey_target = {
> .end_io = flakey_end_io,
> .status = flakey_status,
> .ioctl = flakey_ioctl,
> - .merge = flakey_merge,
> .iterate_devices = flakey_iterate_devices,
> };
>
> diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
> index 53e848c..7dd5fc8 100644
> --- a/drivers/md/dm-linear.c
> +++ b/drivers/md/dm-linear.c
> @@ -130,21 +130,6 @@ static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
> return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
> }
>
> -static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct linear_c *lc = ti->private;
> - struct request_queue *q = bdev_get_queue(lc->dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = lc->dev->bdev;
> - bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int linear_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -162,7 +147,6 @@ static struct target_type linear_target = {
> .map = linear_map,
> .status = linear_status,
> .ioctl = linear_ioctl,
> - .merge = linear_merge,
> .iterate_devices = linear_iterate_devices,
> };
>
> diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
> index 93e0844..4325808 100644
> --- a/drivers/md/dm-log-writes.c
> +++ b/drivers/md/dm-log-writes.c
> @@ -728,21 +728,6 @@ static int log_writes_ioctl(struct dm_target *ti, unsigned int cmd,
> return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
> }
>
> -static int log_writes_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct log_writes_c *lc = ti->private;
> - struct request_queue *q = bdev_get_queue(lc->dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = lc->dev->bdev;
> - bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int log_writes_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn,
> void *data)
> @@ -796,7 +781,6 @@ static struct target_type log_writes_target = {
> .end_io = normal_end_io,
> .status = log_writes_status,
> .ioctl = log_writes_ioctl,
> - .merge = log_writes_merge,
> .message = log_writes_message,
> .iterate_devices = log_writes_iterate_devices,
> .io_hints = log_writes_io_hints,
> diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
> index f83a0f3..274cbec 100644
> --- a/drivers/md/dm-snap.c
> +++ b/drivers/md/dm-snap.c
> @@ -2331,20 +2331,6 @@ static void origin_status(struct dm_target *ti, status_type_t type,
> }
> }
>
> -static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct dm_origin *o = ti->private;
> - struct request_queue *q = bdev_get_queue(o->dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = o->dev->bdev;
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int origin_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -2363,7 +2349,6 @@ static struct target_type origin_target = {
> .resume = origin_resume,
> .postsuspend = origin_postsuspend,
> .status = origin_status,
> - .merge = origin_merge,
> .iterate_devices = origin_iterate_devices,
> };
>
> diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
> index f8b37d4..09bb2fe 100644
> --- a/drivers/md/dm-stripe.c
> +++ b/drivers/md/dm-stripe.c
> @@ -412,26 +412,6 @@ static void stripe_io_hints(struct dm_target *ti,
> blk_limits_io_opt(limits, chunk_size * sc->stripes);
> }
>
> -static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct stripe_c *sc = ti->private;
> - sector_t bvm_sector = bvm->bi_sector;
> - uint32_t stripe;
> - struct request_queue *q;
> -
> - stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
> -
> - q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
> - bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static struct target_type stripe_target = {
> .name = "striped",
> .version = {1, 5, 1},
> @@ -443,7 +423,6 @@ static struct target_type stripe_target = {
> .status = stripe_status,
> .iterate_devices = stripe_iterate_devices,
> .io_hints = stripe_io_hints,
> - .merge = stripe_merge,
> };
>
> int __init dm_stripe_init(void)
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index d9b00b8..19c9b01 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -440,14 +440,6 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
> q->limits.alignment_offset,
> (unsigned long long) start << SECTOR_SHIFT);
>
> - /*
> - * Check if merge fn is supported.
> - * If not we'll force DM to use PAGE_SIZE or
> - * smaller I/O, just to be safe.
> - */
> - if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
> - blk_limits_max_hw_sectors(limits,
> - (unsigned int) (PAGE_SIZE >> 9));
> return 0;
> }
>
> diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
> index 921aafd..03552fe 100644
> --- a/drivers/md/dm-thin.c
> +++ b/drivers/md/dm-thin.c
> @@ -3562,20 +3562,6 @@ static int pool_iterate_devices(struct dm_target *ti,
> return fn(ti, pt->data_dev, 0, ti->len, data);
> }
>
> -static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct pool_c *pt = ti->private;
> - struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = pt->data_dev->bdev;
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
> {
> struct pool *pool = pt->pool;
> @@ -3667,7 +3653,6 @@ static struct target_type pool_target = {
> .resume = pool_resume,
> .message = pool_message,
> .status = pool_status,
> - .merge = pool_merge,
> .iterate_devices = pool_iterate_devices,
> .io_hints = pool_io_hints,
> };
> @@ -3992,21 +3977,6 @@ err:
> DMEMIT("Error");
> }
>
> -static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct thin_c *tc = ti->private;
> - struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = tc->pool_dev->bdev;
> - bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int thin_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -4041,7 +4011,6 @@ static struct target_type thin_target = {
> .presuspend = thin_presuspend,
> .postsuspend = thin_postsuspend,
> .status = thin_status,
> - .merge = thin_merge,
> .iterate_devices = thin_iterate_devices,
> };
>
> diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
> index 66616db..3b85460 100644
> --- a/drivers/md/dm-verity.c
> +++ b/drivers/md/dm-verity.c
> @@ -648,21 +648,6 @@ static int verity_ioctl(struct dm_target *ti, unsigned cmd,
> cmd, arg);
> }
>
> -static int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size)
> -{
> - struct dm_verity *v = ti->private;
> - struct request_queue *q = bdev_get_queue(v->data_dev->bdev);
> -
> - if (!q->merge_bvec_fn)
> - return max_size;
> -
> - bvm->bi_bdev = v->data_dev->bdev;
> - bvm->bi_sector = verity_map_sector(v, bvm->bi_sector);
> -
> - return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
> -}
> -
> static int verity_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -995,7 +980,6 @@ static struct target_type verity_target = {
> .map = verity_map,
> .status = verity_status,
> .ioctl = verity_ioctl,
> - .merge = verity_merge,
> .iterate_devices = verity_iterate_devices,
> .io_hints = verity_io_hints,
> };
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 34f6063..f732a7a 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -121,9 +121,8 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
> #define DMF_FREEING 3
> #define DMF_DELETING 4
> #define DMF_NOFLUSH_SUSPENDING 5
> -#define DMF_MERGE_IS_OPTIONAL 6
> -#define DMF_DEFERRED_REMOVE 7
> -#define DMF_SUSPENDED_INTERNALLY 8
> +#define DMF_DEFERRED_REMOVE 6
> +#define DMF_SUSPENDED_INTERNALLY 7
>
> /*
> * A dummy definition to make RCU happy.
> @@ -1717,60 +1716,6 @@ static void __split_and_process_bio(struct mapped_device *md,
> * CRUD END
> *---------------------------------------------------------------*/
>
> -static int dm_merge_bvec(struct request_queue *q,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct mapped_device *md = q->queuedata;
> - struct dm_table *map = dm_get_live_table_fast(md);
> - struct dm_target *ti;
> - sector_t max_sectors;
> - int max_size = 0;
> -
> - if (unlikely(!map))
> - goto out;
> -
> - ti = dm_table_find_target(map, bvm->bi_sector);
> - if (!dm_target_is_valid(ti))
> - goto out;
> -
> - /*
> - * Find maximum amount of I/O that won't need splitting
> - */
> - max_sectors = min(max_io_len(bvm->bi_sector, ti),
> - (sector_t) queue_max_sectors(q));
> - max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
> - if (unlikely(max_size < 0)) /* this shouldn't _ever_ happen */
> - max_size = 0;
> -
> - /*
> - * merge_bvec_fn() returns number of bytes
> - * it can accept at this offset
> - * max is precomputed maximal io size
> - */
> - if (max_size && ti->type->merge)
> - max_size = ti->type->merge(ti, bvm, biovec, max_size);
> - /*
> - * If the target doesn't support merge method and some of the devices
> - * provided their merge_bvec method (we know this by looking for the
> - * max_hw_sectors that dm_set_device_limits may set), then we can't
> - * allow bios with multiple vector entries. So always set max_size
> - * to 0, and the code below allows just one page.
> - */
> - else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
> - max_size = 0;
> -
> -out:
> - dm_put_live_table_fast(md);
> - /*
> - * Always allow an entire first page
> - */
> - if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
> - max_size = biovec->bv_len;
> -
> - return max_size;
> -}
> -
> /*
> * The request function that just remaps the bio built up by
> * dm_merge_bvec.
> @@ -2477,59 +2422,6 @@ static void __set_size(struct mapped_device *md, sector_t size)
> }
>
> /*
> - * Return 1 if the queue has a compulsory merge_bvec_fn function.
> - *
> - * If this function returns 0, then the device is either a non-dm
> - * device without a merge_bvec_fn, or it is a dm device that is
> - * able to split any bios it receives that are too big.
> - */
> -int dm_queue_merge_is_compulsory(struct request_queue *q)
> -{
> - struct mapped_device *dev_md;
> -
> - if (!q->merge_bvec_fn)
> - return 0;
> -
> - if (q->make_request_fn == dm_make_request) {
> - dev_md = q->queuedata;
> - if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
> - return 0;
> - }
> -
> - return 1;
> -}
> -
> -static int dm_device_merge_is_compulsory(struct dm_target *ti,
> - struct dm_dev *dev, sector_t start,
> - sector_t len, void *data)
> -{
> - struct block_device *bdev = dev->bdev;
> - struct request_queue *q = bdev_get_queue(bdev);
> -
> - return dm_queue_merge_is_compulsory(q);
> -}
> -
> -/*
> - * Return 1 if it is acceptable to ignore merge_bvec_fn based
> - * on the properties of the underlying devices.
> - */
> -static int dm_table_merge_is_optional(struct dm_table *table)
> -{
> - unsigned i = 0;
> - struct dm_target *ti;
> -
> - while (i < dm_table_get_num_targets(table)) {
> - ti = dm_table_get_target(table, i++);
> -
> - if (ti->type->iterate_devices &&
> - ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
> - return 0;
> - }
> -
> - return 1;
> -}
> -
> -/*
> * Returns old map, which caller must destroy.
> */
> static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
> @@ -2538,7 +2430,6 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
> struct dm_table *old_map;
> struct request_queue *q = md->queue;
> sector_t size;
> - int merge_is_optional;
>
> size = dm_table_get_size(t);
>
> @@ -2564,17 +2455,11 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
>
> __bind_mempools(md, t);
>
> - merge_is_optional = dm_table_merge_is_optional(t);
> -
> old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
> rcu_assign_pointer(md->map, t);
> md->immutable_target_type = dm_table_get_immutable_target_type(t);
>
> dm_table_set_restrictions(t, q, limits);
> - if (merge_is_optional)
> - set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
> - else
> - clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
> if (old_map)
> dm_sync_table(md);
>
> @@ -2852,7 +2737,6 @@ int dm_setup_md_queue(struct mapped_device *md)
> case DM_TYPE_BIO_BASED:
> dm_init_old_md_queue(md);
> blk_queue_make_request(md->queue, dm_make_request);
> - blk_queue_merge_bvec(md->queue, dm_merge_bvec);
> break;
> }
>
> diff --git a/drivers/md/dm.h b/drivers/md/dm.h
> index 6123c2b..7d61cca 100644
> --- a/drivers/md/dm.h
> +++ b/drivers/md/dm.h
> @@ -77,8 +77,6 @@ bool dm_table_mq_request_based(struct dm_table *t);
> void dm_table_free_md_mempools(struct dm_table *t);
> struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
>
> -int dm_queue_merge_is_compulsory(struct request_queue *q);
> -
> void dm_lock_md_type(struct mapped_device *md);
> void dm_unlock_md_type(struct mapped_device *md);
> void dm_set_md_type(struct mapped_device *md, unsigned type);
> diff --git a/drivers/md/linear.c b/drivers/md/linear.c
> index fa7d577..8721ef9 100644
> --- a/drivers/md/linear.c
> +++ b/drivers/md/linear.c
> @@ -52,48 +52,6 @@ static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
> return conf->disks + lo;
> }
>
> -/**
> - * linear_mergeable_bvec -- tell bio layer if two requests can be merged
> - * @q: request queue
> - * @bvm: properties of new bio
> - * @biovec: the request that could be merged to it.
> - *
> - * Return amount of bytes we can take at this offset
> - */
> -static int linear_mergeable_bvec(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct dev_info *dev0;
> - unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
> - sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
> - int maxbytes = biovec->bv_len;
> - struct request_queue *subq;
> -
> - dev0 = which_dev(mddev, sector);
> - maxsectors = dev0->end_sector - sector;
> - subq = bdev_get_queue(dev0->rdev->bdev);
> - if (subq->merge_bvec_fn) {
> - bvm->bi_bdev = dev0->rdev->bdev;
> - bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors;
> - maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm,
> - biovec));
> - }
> -
> - if (maxsectors < bio_sectors)
> - maxsectors = 0;
> - else
> - maxsectors -= bio_sectors;
> -
> - if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
> - return maxbytes;
> -
> - if (maxsectors > (maxbytes >> 9))
> - return maxbytes;
> - else
> - return maxsectors << 9;
> -}
> -
> static int linear_congested(struct mddev *mddev, int bits)
> {
> struct linear_conf *conf;
> @@ -338,7 +296,6 @@ static struct md_personality linear_personality =
> .size = linear_size,
> .quiesce = linear_quiesce,
> .congested = linear_congested,
> - .mergeable_bvec = linear_mergeable_bvec,
> };
>
> static int __init linear_init (void)
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 046b3c9..f101981 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -352,29 +352,6 @@ static int md_congested(void *data, int bits)
> return mddev_congested(mddev, bits);
> }
>
> -static int md_mergeable_bvec(struct request_queue *q,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct mddev *mddev = q->queuedata;
> - int ret;
> - rcu_read_lock();
> - if (mddev->suspended) {
> - /* Must always allow one vec */
> - if (bvm->bi_size == 0)
> - ret = biovec->bv_len;
> - else
> - ret = 0;
> - } else {
> - struct md_personality *pers = mddev->pers;
> - if (pers && pers->mergeable_bvec)
> - ret = pers->mergeable_bvec(mddev, bvm, biovec);
> - else
> - ret = biovec->bv_len;
> - }
> - rcu_read_unlock();
> - return ret;
> -}
> /*
> * Generic flush handling for md
> */
> @@ -5165,7 +5142,6 @@ int md_run(struct mddev *mddev)
> if (mddev->queue) {
> mddev->queue->backing_dev_info.congested_data = mddev;
> mddev->queue->backing_dev_info.congested_fn = md_congested;
> - blk_queue_merge_bvec(mddev->queue, md_mergeable_bvec);
> }
> if (pers->sync_request) {
> if (mddev->kobj.sd &&
> @@ -5293,7 +5269,6 @@ static void md_clean(struct mddev *mddev)
> mddev->changed = 0;
> mddev->degraded = 0;
> mddev->safemode = 0;
> - mddev->merge_check_needed = 0;
> mddev->bitmap_info.offset = 0;
> mddev->bitmap_info.default_offset = 0;
> mddev->bitmap_info.default_space = 0;
> @@ -5489,7 +5464,6 @@ static int do_md_stop(struct mddev *mddev, int mode,
>
> __md_stop_writes(mddev);
> __md_stop(mddev);
> - mddev->queue->merge_bvec_fn = NULL;
> mddev->queue->backing_dev_info.congested_fn = NULL;
>
> /* tell userspace to handle 'inactive' */
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 4046a6c..cf7141a 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -133,10 +133,6 @@ enum flag_bits {
> Bitmap_sync, /* ..actually, not quite In_sync. Need a
> * bitmap-based recovery to get fully in sync
> */
> - Unmerged, /* device is being added to array and should
> - * be considerred for bvec_merge_fn but not
> - * yet for actual IO
> - */
> WriteMostly, /* Avoid reading if at all possible */
> AutoDetected, /* added by auto-detect */
> Blocked, /* An error occurred but has not yet
> @@ -373,10 +369,6 @@ struct mddev {
> int degraded; /* whether md should consider
> * adding a spare
> */
> - int merge_check_needed; /* at least one
> - * member device
> - * has a
> - * merge_bvec_fn */
>
> atomic_t recovery_active; /* blocks scheduled, but not written */
> wait_queue_head_t recovery_wait;
> @@ -531,10 +523,6 @@ struct md_personality
> /* congested implements bdi.congested_fn().
> * Will not be called while array is 'suspended' */
> int (*congested)(struct mddev *mddev, int bits);
> - /* mergeable_bvec is use to implement ->merge_bvec_fn */
> - int (*mergeable_bvec)(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec);
> };
>
> struct md_sysfs_entry {
> diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
> index ac3ede2..7ee27fb 100644
> --- a/drivers/md/multipath.c
> +++ b/drivers/md/multipath.c
> @@ -257,18 +257,6 @@ static int multipath_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> disk_stack_limits(mddev->gendisk, rdev->bdev,
> rdev->data_offset << 9);
>
> - /* as we don't honour merge_bvec_fn, we must never risk
> - * violating it, so limit ->max_segments to one, lying
> - * within a single page.
> - * (Note: it is very unlikely that a device with
> - * merge_bvec_fn will be involved in multipath.)
> - */
> - if (q->merge_bvec_fn) {
> - blk_queue_max_segments(mddev->queue, 1);
> - blk_queue_segment_boundary(mddev->queue,
> - PAGE_CACHE_SIZE - 1);
> - }
> -
> spin_lock_irq(&conf->device_lock);
> mddev->degraded--;
> rdev->raid_disk = path;
> @@ -432,15 +420,6 @@ static int multipath_run (struct mddev *mddev)
> disk_stack_limits(mddev->gendisk, rdev->bdev,
> rdev->data_offset << 9);
>
> - /* as we don't honour merge_bvec_fn, we must never risk
> - * violating it, not that we ever expect a device with
> - * a merge_bvec_fn to be involved in multipath */
> - if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
> - blk_queue_max_segments(mddev->queue, 1);
> - blk_queue_segment_boundary(mddev->queue,
> - PAGE_CACHE_SIZE - 1);
> - }
> -
> if (!test_bit(Faulty, &rdev->flags))
> working_disks++;
> }
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index 6a68ef5..1440bd4 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -192,9 +192,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
> disk_stack_limits(mddev->gendisk, rdev1->bdev,
> rdev1->data_offset << 9);
>
> - if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
> - conf->has_merge_bvec = 1;
> -
> if (!smallest || (rdev1->sectors < smallest->sectors))
> smallest = rdev1;
> cnt++;
> @@ -351,58 +348,6 @@ static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
> + sector_div(sector, zone->nb_dev)];
> }
>
> -/**
> - * raid0_mergeable_bvec -- tell bio layer if two requests can be merged
> - * @mddev: the md device
> - * @bvm: properties of new bio
> - * @biovec: the request that could be merged to it.
> - *
> - * Return amount of bytes we can accept at this offset
> - */
> -static int raid0_mergeable_bvec(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct r0conf *conf = mddev->private;
> - sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
> - sector_t sector_offset = sector;
> - int max;
> - unsigned int chunk_sectors = mddev->chunk_sectors;
> - unsigned int bio_sectors = bvm->bi_size >> 9;
> - struct strip_zone *zone;
> - struct md_rdev *rdev;
> - struct request_queue *subq;
> -
> - if (is_power_of_2(chunk_sectors))
> - max = (chunk_sectors - ((sector & (chunk_sectors-1))
> - + bio_sectors)) << 9;
> - else
> - max = (chunk_sectors - (sector_div(sector, chunk_sectors)
> - + bio_sectors)) << 9;
> - if (max < 0)
> - max = 0; /* bio_add cannot handle a negative return */
> - if (max <= biovec->bv_len && bio_sectors == 0)
> - return biovec->bv_len;
> - if (max < biovec->bv_len)
> - /* too small already, no need to check further */
> - return max;
> - if (!conf->has_merge_bvec)
> - return max;
> -
> - /* May need to check subordinate device */
> - sector = sector_offset;
> - zone = find_zone(mddev->private, &sector_offset);
> - rdev = map_sector(mddev, zone, sector, &sector_offset);
> - subq = bdev_get_queue(rdev->bdev);
> - if (subq->merge_bvec_fn) {
> - bvm->bi_bdev = rdev->bdev;
> - bvm->bi_sector = sector_offset + zone->dev_start +
> - rdev->data_offset;
> - return min(max, subq->merge_bvec_fn(subq, bvm, biovec));
> - } else
> - return max;
> -}
> -
> static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
> {
> sector_t array_sectors = 0;
> @@ -725,7 +670,6 @@ static struct md_personality raid0_personality=
> .takeover = raid0_takeover,
> .quiesce = raid0_quiesce,
> .congested = raid0_congested,
> - .mergeable_bvec = raid0_mergeable_bvec,
> };
>
> static int __init raid0_init (void)
> diff --git a/drivers/md/raid0.h b/drivers/md/raid0.h
> index 05539d9..7127a62 100644
> --- a/drivers/md/raid0.h
> +++ b/drivers/md/raid0.h
> @@ -12,8 +12,6 @@ struct r0conf {
> struct md_rdev **devlist; /* lists of rdevs, pointed to
> * by strip_zone->dev */
> int nr_strip_zones;
> - int has_merge_bvec; /* at least one member has
> - * a merge_bvec_fn */
> };
>
> #endif
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 9157a29..478878f 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -557,7 +557,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
> rdev = rcu_dereference(conf->mirrors[disk].rdev);
> if (r1_bio->bios[disk] == IO_BLOCKED
> || rdev == NULL
> - || test_bit(Unmerged, &rdev->flags)
> || test_bit(Faulty, &rdev->flags))
> continue;
> if (!test_bit(In_sync, &rdev->flags) &&
> @@ -708,38 +707,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
> return best_disk;
> }
>
> -static int raid1_mergeable_bvec(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct r1conf *conf = mddev->private;
> - sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
> - int max = biovec->bv_len;
> -
> - if (mddev->merge_check_needed) {
> - int disk;
> - rcu_read_lock();
> - for (disk = 0; disk < conf->raid_disks * 2; disk++) {
> - struct md_rdev *rdev = rcu_dereference(
> - conf->mirrors[disk].rdev);
> - if (rdev && !test_bit(Faulty, &rdev->flags)) {
> - struct request_queue *q =
> - bdev_get_queue(rdev->bdev);
> - if (q->merge_bvec_fn) {
> - bvm->bi_sector = sector +
> - rdev->data_offset;
> - bvm->bi_bdev = rdev->bdev;
> - max = min(max, q->merge_bvec_fn(
> - q, bvm, biovec));
> - }
> - }
> - }
> - rcu_read_unlock();
> - }
> - return max;
> -
> -}
> -
> static int raid1_congested(struct mddev *mddev, int bits)
> {
> struct r1conf *conf = mddev->private;
> @@ -1268,8 +1235,7 @@ read_again:
> break;
> }
> r1_bio->bios[i] = NULL;
> - if (!rdev || test_bit(Faulty, &rdev->flags)
> - || test_bit(Unmerged, &rdev->flags)) {
> + if (!rdev || test_bit(Faulty, &rdev->flags)) {
> if (i < conf->raid_disks)
> set_bit(R1BIO_Degraded, &r1_bio->state);
> continue;
> @@ -1614,7 +1580,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> struct raid1_info *p;
> int first = 0;
> int last = conf->raid_disks - 1;
> - struct request_queue *q = bdev_get_queue(rdev->bdev);
>
> if (mddev->recovery_disabled == conf->recovery_disabled)
> return -EBUSY;
> @@ -1622,11 +1587,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> if (rdev->raid_disk >= 0)
> first = last = rdev->raid_disk;
>
> - if (q->merge_bvec_fn) {
> - set_bit(Unmerged, &rdev->flags);
> - mddev->merge_check_needed = 1;
> - }
> -
> for (mirror = first; mirror <= last; mirror++) {
> p = conf->mirrors+mirror;
> if (!p->rdev) {
> @@ -1658,19 +1618,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> break;
> }
> }
> - if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
> - /* Some requests might not have seen this new
> - * merge_bvec_fn. We must wait for them to complete
> - * before merging the device fully.
> - * First we make sure any code which has tested
> - * our function has submitted the request, then
> - * we wait for all outstanding requests to complete.
> - */
> - synchronize_sched();
> - freeze_array(conf, 0);
> - unfreeze_array(conf);
> - clear_bit(Unmerged, &rdev->flags);
> - }
> md_integrity_add_rdev(rdev, mddev);
> if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
> queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> @@ -2807,8 +2754,6 @@ static struct r1conf *setup_conf(struct mddev *mddev)
> goto abort;
> disk->rdev = rdev;
> q = bdev_get_queue(rdev->bdev);
> - if (q->merge_bvec_fn)
> - mddev->merge_check_needed = 1;
>
> disk->head_position = 0;
> disk->seq_start = MaxSector;
> @@ -3173,7 +3118,6 @@ static struct md_personality raid1_personality =
> .quiesce = raid1_quiesce,
> .takeover = raid1_takeover,
> .congested = raid1_congested,
> - .mergeable_bvec = raid1_mergeable_bvec,
> };
>
> static int __init raid_init(void)
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index e793ab6..a46c402 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -672,93 +672,6 @@ static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
> return (vchunk << geo->chunk_shift) + offset;
> }
>
> -/**
> - * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
> - * @mddev: the md device
> - * @bvm: properties of new bio
> - * @biovec: the request that could be merged to it.
> - *
> - * Return amount of bytes we can accept at this offset
> - * This requires checking for end-of-chunk if near_copies != raid_disks,
> - * and for subordinate merge_bvec_fns if merge_check_needed.
> - */
> -static int raid10_mergeable_bvec(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - struct r10conf *conf = mddev->private;
> - sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
> - int max;
> - unsigned int chunk_sectors;
> - unsigned int bio_sectors = bvm->bi_size >> 9;
> - struct geom *geo = &conf->geo;
> -
> - chunk_sectors = (conf->geo.chunk_mask & conf->prev.chunk_mask) + 1;
> - if (conf->reshape_progress != MaxSector &&
> - ((sector >= conf->reshape_progress) !=
> - conf->mddev->reshape_backwards))
> - geo = &conf->prev;
> -
> - if (geo->near_copies < geo->raid_disks) {
> - max = (chunk_sectors - ((sector & (chunk_sectors - 1))
> - + bio_sectors)) << 9;
> - if (max < 0)
> - /* bio_add cannot handle a negative return */
> - max = 0;
> - if (max <= biovec->bv_len && bio_sectors == 0)
> - return biovec->bv_len;
> - } else
> - max = biovec->bv_len;
> -
> - if (mddev->merge_check_needed) {
> - struct {
> - struct r10bio r10_bio;
> - struct r10dev devs[conf->copies];
> - } on_stack;
> - struct r10bio *r10_bio = &on_stack.r10_bio;
> - int s;
> - if (conf->reshape_progress != MaxSector) {
> - /* Cannot give any guidance during reshape */
> - if (max <= biovec->bv_len && bio_sectors == 0)
> - return biovec->bv_len;
> - return 0;
> - }
> - r10_bio->sector = sector;
> - raid10_find_phys(conf, r10_bio);
> - rcu_read_lock();
> - for (s = 0; s < conf->copies; s++) {
> - int disk = r10_bio->devs[s].devnum;
> - struct md_rdev *rdev = rcu_dereference(
> - conf->mirrors[disk].rdev);
> - if (rdev && !test_bit(Faulty, &rdev->flags)) {
> - struct request_queue *q =
> - bdev_get_queue(rdev->bdev);
> - if (q->merge_bvec_fn) {
> - bvm->bi_sector = r10_bio->devs[s].addr
> - + rdev->data_offset;
> - bvm->bi_bdev = rdev->bdev;
> - max = min(max, q->merge_bvec_fn(
> - q, bvm, biovec));
> - }
> - }
> - rdev = rcu_dereference(conf->mirrors[disk].replacement);
> - if (rdev && !test_bit(Faulty, &rdev->flags)) {
> - struct request_queue *q =
> - bdev_get_queue(rdev->bdev);
> - if (q->merge_bvec_fn) {
> - bvm->bi_sector = r10_bio->devs[s].addr
> - + rdev->data_offset;
> - bvm->bi_bdev = rdev->bdev;
> - max = min(max, q->merge_bvec_fn(
> - q, bvm, biovec));
> - }
> - }
> - }
> - rcu_read_unlock();
> - }
> - return max;
> -}
> -
> /*
> * This routine returns the disk from which the requested read should
> * be done. There is a per-array 'next expected sequential IO' sector
> @@ -821,12 +734,10 @@ retry:
> disk = r10_bio->devs[slot].devnum;
> rdev = rcu_dereference(conf->mirrors[disk].replacement);
> if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
> - test_bit(Unmerged, &rdev->flags) ||
> r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
> rdev = rcu_dereference(conf->mirrors[disk].rdev);
> if (rdev == NULL ||
> - test_bit(Faulty, &rdev->flags) ||
> - test_bit(Unmerged, &rdev->flags))
> + test_bit(Faulty, &rdev->flags))
> continue;
> if (!test_bit(In_sync, &rdev->flags) &&
> r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
> @@ -1326,11 +1237,9 @@ retry_write:
> blocked_rdev = rrdev;
> break;
> }
> - if (rdev && (test_bit(Faulty, &rdev->flags)
> - || test_bit(Unmerged, &rdev->flags)))
> + if (rdev && (test_bit(Faulty, &rdev->flags)))
> rdev = NULL;
> - if (rrdev && (test_bit(Faulty, &rrdev->flags)
> - || test_bit(Unmerged, &rrdev->flags)))
> + if (rrdev && (test_bit(Faulty, &rrdev->flags)))
> rrdev = NULL;
>
> r10_bio->devs[i].bio = NULL;
> @@ -1777,7 +1686,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> int mirror;
> int first = 0;
> int last = conf->geo.raid_disks - 1;
> - struct request_queue *q = bdev_get_queue(rdev->bdev);
>
> if (mddev->recovery_cp < MaxSector)
> /* only hot-add to in-sync arrays, as recovery is
> @@ -1790,11 +1698,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> if (rdev->raid_disk >= 0)
> first = last = rdev->raid_disk;
>
> - if (q->merge_bvec_fn) {
> - set_bit(Unmerged, &rdev->flags);
> - mddev->merge_check_needed = 1;
> - }
> -
> if (rdev->saved_raid_disk >= first &&
> conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
> mirror = rdev->saved_raid_disk;
> @@ -1833,19 +1736,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> rcu_assign_pointer(p->rdev, rdev);
> break;
> }
> - if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
> - /* Some requests might not have seen this new
> - * merge_bvec_fn. We must wait for them to complete
> - * before merging the device fully.
> - * First we make sure any code which has tested
> - * our function has submitted the request, then
> - * we wait for all outstanding requests to complete.
> - */
> - synchronize_sched();
> - freeze_array(conf, 0);
> - unfreeze_array(conf);
> - clear_bit(Unmerged, &rdev->flags);
> - }
> md_integrity_add_rdev(rdev, mddev);
> if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
> queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> @@ -2404,7 +2294,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
> d = r10_bio->devs[sl].devnum;
> rdev = rcu_dereference(conf->mirrors[d].rdev);
> if (rdev &&
> - !test_bit(Unmerged, &rdev->flags) &&
> test_bit(In_sync, &rdev->flags) &&
> is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
> &first_bad, &bad_sectors) == 0) {
> @@ -2458,7 +2347,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
> d = r10_bio->devs[sl].devnum;
> rdev = rcu_dereference(conf->mirrors[d].rdev);
> if (!rdev ||
> - test_bit(Unmerged, &rdev->flags) ||
> !test_bit(In_sync, &rdev->flags))
> continue;
>
> @@ -3652,8 +3540,6 @@ static int run(struct mddev *mddev)
> disk->rdev = rdev;
> }
> q = bdev_get_queue(rdev->bdev);
> - if (q->merge_bvec_fn)
> - mddev->merge_check_needed = 1;
> diff = (rdev->new_data_offset - rdev->data_offset);
> if (!mddev->reshape_backwards)
> diff = -diff;
> @@ -4706,7 +4592,6 @@ static struct md_personality raid10_personality =
> .start_reshape = raid10_start_reshape,
> .finish_reshape = raid10_finish_reshape,
> .congested = raid10_congested,
> - .mergeable_bvec = raid10_mergeable_bvec,
> };
>
> static int __init raid_init(void)
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index b6c6ace..18d2b23 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -4625,35 +4625,6 @@ static int raid5_congested(struct mddev *mddev, int bits)
> return 0;
> }
>
> -/* We want read requests to align with chunks where possible,
> - * but write requests don't need to.
> - */
> -static int raid5_mergeable_bvec(struct mddev *mddev,
> - struct bvec_merge_data *bvm,
> - struct bio_vec *biovec)
> -{
> - sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
> - int max;
> - unsigned int chunk_sectors = mddev->chunk_sectors;
> - unsigned int bio_sectors = bvm->bi_size >> 9;
> -
> - /*
> - * always allow writes to be mergeable, read as well if array
> - * is degraded as we'll go through stripe cache anyway.
> - */
> - if ((bvm->bi_rw & 1) == WRITE || mddev->degraded)
> - return biovec->bv_len;
> -
> - if (mddev->new_chunk_sectors < mddev->chunk_sectors)
> - chunk_sectors = mddev->new_chunk_sectors;
> - max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
> - if (max < 0) max = 0;
> - if (max <= biovec->bv_len && bio_sectors == 0)
> - return biovec->bv_len;
> - else
> - return max;
> -}
> -
> static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
> {
> sector_t sector = bio->bi_iter.bi_sector + get_start_sect(bio->bi_bdev);
> @@ -7722,7 +7693,6 @@ static struct md_personality raid6_personality =
> .quiesce = raid5_quiesce,
> .takeover = raid6_takeover,
> .congested = raid5_congested,
> - .mergeable_bvec = raid5_mergeable_bvec,
> };
> static struct md_personality raid5_personality =
> {
> @@ -7746,7 +7716,6 @@ static struct md_personality raid5_personality =
> .quiesce = raid5_quiesce,
> .takeover = raid5_takeover,
> .congested = raid5_congested,
> - .mergeable_bvec = raid5_mergeable_bvec,
> };
>
> static struct md_personality raid4_personality =
> @@ -7771,7 +7740,6 @@ static struct md_personality raid4_personality =
> .quiesce = raid5_quiesce,
> .takeover = raid4_takeover,
> .congested = raid5_congested,
> - .mergeable_bvec = raid5_mergeable_bvec,
> };
>
> static int __init raid5_init(void)
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 93b81a2..6927b76 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -239,14 +239,6 @@ typedef int (prep_rq_fn) (struct request_queue *, struct request *);
> typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
>
> struct bio_vec;
> -struct bvec_merge_data {
> - struct block_device *bi_bdev;
> - sector_t bi_sector;
> - unsigned bi_size;
> - unsigned long bi_rw;
> -};
> -typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
> - struct bio_vec *);
> typedef void (softirq_done_fn)(struct request *);
> typedef int (dma_drain_needed_fn)(struct request *);
> typedef int (lld_busy_fn) (struct request_queue *q);
> @@ -331,7 +323,6 @@ struct request_queue {
> make_request_fn *make_request_fn;
> prep_rq_fn *prep_rq_fn;
> unprep_rq_fn *unprep_rq_fn;
> - merge_bvec_fn *merge_bvec_fn;
> softirq_done_fn *softirq_done_fn;
> rq_timed_out_fn *rq_timed_out_fn;
> dma_drain_needed_fn *dma_drain_needed;
> @@ -1041,7 +1032,6 @@ extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
> extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
> extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
> extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
> -extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
> extern void blk_queue_dma_alignment(struct request_queue *, int);
> extern void blk_queue_update_dma_alignment(struct request_queue *, int);
> extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> index 51cc1de..76d23fa 100644
> --- a/include/linux/device-mapper.h
> +++ b/include/linux/device-mapper.h
> @@ -82,9 +82,6 @@ typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
> typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
> unsigned long arg);
>
> -typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
> - struct bio_vec *biovec, int max_size);
> -
> /*
> * These iteration functions are typically used to check (and combine)
> * properties of underlying devices.
> @@ -160,7 +157,6 @@ struct target_type {
> dm_status_fn status;
> dm_message_fn message;
> dm_ioctl_fn ioctl;
> - dm_merge_fn merge;
> dm_busy_fn busy;
> dm_iterate_devices_fn iterate_devices;
> dm_io_hints_fn io_hints;

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