Re: [Cluster-devel] [PATCH 23/27] block: add a bdev_max_discard_sectors helper

Andreas Gruenbacher
2022-04-06T09:53:53Z

On Wed, Apr 6, 2022 at 8:07 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Add a helper to query the number of sectors support per each discard bio
> based on the block device and use this helper to stop various places from
> poking into the request_queue to see if discard is supported and if so how
> much. This mirrors what is done e.g. for write zeroes as well.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> block/blk-core.c | 2 +-
> block/blk-lib.c | 2 +-
> block/ioctl.c | 3 +--
> drivers/block/drbd/drbd_main.c | 2 +-
> drivers/block/drbd/drbd_nl.c | 12 +++++++-----
> drivers/block/drbd/drbd_receiver.c | 5 ++---
> drivers/block/loop.c | 9 +++------
> drivers/block/rnbd/rnbd-srv-dev.h | 6 +-----
> drivers/block/xen-blkback/xenbus.c | 2 +-
> drivers/md/bcache/request.c | 4 ++--
> drivers/md/bcache/super.c | 2 +-
> drivers/md/bcache/sysfs.c | 2 +-
> drivers/md/dm-cache-target.c | 9 +--------
> drivers/md/dm-clone-target.c | 9 +--------
> drivers/md/dm-io.c | 2 +-
> drivers/md/dm-log-writes.c | 3 +--
> drivers/md/dm-raid.c | 9 ++-------
> drivers/md/dm-table.c | 4 +---
> drivers/md/dm-thin.c | 9 +--------
> drivers/md/dm.c | 2 +-
> drivers/md/md-linear.c | 4 ++--
> drivers/md/raid0.c | 2 +-
> drivers/md/raid1.c | 6 +++---
> drivers/md/raid10.c | 8 ++++----
> drivers/md/raid5-cache.c | 2 +-
> drivers/target/target_core_device.c | 8 +++-----
> fs/btrfs/extent-tree.c | 4 ++--
> fs/btrfs/ioctl.c | 2 +-
> fs/exfat/file.c | 2 +-
> fs/exfat/super.c | 10 +++-------
> fs/ext4/ioctl.c | 10 +++-------
> fs/ext4/super.c | 10 +++-------
> fs/f2fs/f2fs.h | 3 +--
> fs/f2fs/segment.c | 6 ++----
> fs/fat/file.c | 2 +-
> fs/fat/inode.c | 10 +++-------
> fs/gfs2/rgrp.c | 2 +-
> fs/jbd2/journal.c | 7 ++-----
> fs/jfs/ioctl.c | 2 +-
> fs/jfs/super.c | 8 ++------
> fs/nilfs2/ioctl.c | 2 +-
> fs/ntfs3/file.c | 2 +-
> fs/ntfs3/super.c | 2 +-
> fs/ocfs2/ioctl.c | 2 +-
> fs/xfs/xfs_discard.c | 2 +-
> fs/xfs/xfs_super.c | 12 ++++--------
> include/linux/blkdev.h | 5 +++++
> mm/swapfile.c | 17 ++---------------
> 48 files changed, 87 insertions(+), 163 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 937bb6b863317..b5c3a8049134c 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -820,7 +820,7 @@ void submit_bio_noacct(struct bio *bio)
>
> switch (bio_op(bio)) {
> case REQ_OP_DISCARD:
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(bdev))
> goto not_supported;
> break;
> case REQ_OP_SECURE_ERASE:
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index 2ae32a722851c..8b4b66d3a9bfc 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -53,7 +53,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
> return -EOPNOTSUPP;
> op = REQ_OP_SECURE_ERASE;
> } else {
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(bdev))
> return -EOPNOTSUPP;
> op = REQ_OP_DISCARD;
> }
> diff --git a/block/ioctl.c b/block/ioctl.c
> index ad3771b268b81..c2cd3ba5290ce 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -87,14 +87,13 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
> {
> uint64_t range[2];
> uint64_t start, len;
> - struct request_queue *q = bdev_get_queue(bdev);
> struct inode *inode = bdev->bd_inode;
> int err;
>
> if (!(mode & FMODE_WRITE))
> return -EBADF;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(bdev))
> return -EOPNOTSUPP;
>
> if (copy_from_user(range, (void __user *)arg, sizeof(range)))
> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> index 9d43aadde19ad..8fd89a1b0b7b3 100644
> --- a/drivers/block/drbd/drbd_main.c
> +++ b/drivers/block/drbd/drbd_main.c
> @@ -942,7 +942,7 @@ int drbd_send_sizes(struct drbd_peer_device *peer_device, int trigger_reply, enu
> cpu_to_be32(bdev_alignment_offset(bdev));
> p->qlim->io_min = cpu_to_be32(bdev_io_min(bdev));
> p->qlim->io_opt = cpu_to_be32(bdev_io_opt(bdev));
> - p->qlim->discard_enabled = blk_queue_discard(q);
> + p->qlim->discard_enabled = !!bdev_max_discard_sectors(bdev);
> p->qlim->write_same_capable = 0;
> put_ldev(device);
> } else {
> diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
> index 40bb0b356a6d6..8e28e0a8e5e41 100644
> --- a/drivers/block/drbd/drbd_nl.c
> +++ b/drivers/block/drbd/drbd_nl.c
> @@ -1210,7 +1210,7 @@ static void decide_on_discard_support(struct drbd_device *device,
> first_peer_device(device)->connection;
> struct request_queue *q = device->rq_queue;
>
> - if (bdev && !blk_queue_discard(bdev->backing_bdev->bd_disk->queue))
> + if (bdev && !bdev_max_discard_sectors(bdev->backing_bdev))
> goto not_supported;
>
> if (connection->cstate >= C_CONNECTED &&
> @@ -1439,14 +1439,15 @@ static bool write_ordering_changed(struct disk_conf *a, struct disk_conf *b)
> static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *disk_conf,
> struct drbd_backing_dev *nbc)
> {
> - struct request_queue * const q = nbc->backing_bdev->bd_disk->queue;
> + struct block_device *bdev = nbc->backing_bdev;
> + struct request_queue *q = bdev->bd_disk->queue;
>
> if (disk_conf->al_extents < DRBD_AL_EXTENTS_MIN)
> disk_conf->al_extents = DRBD_AL_EXTENTS_MIN;
> if (disk_conf->al_extents > drbd_al_extents_max(nbc))
> disk_conf->al_extents = drbd_al_extents_max(nbc);
>
> - if (!blk_queue_discard(q)) {
> + if (!bdev_max_discard_sectors(bdev)) {
> if (disk_conf->rs_discard_granularity) {
> disk_conf->rs_discard_granularity = 0; /* disable feature */
> drbd_info(device, "rs_discard_granularity feature disabled\n");
> @@ -1455,6 +1456,7 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis
>
> if (disk_conf->rs_discard_granularity) {
> int orig_value = disk_conf->rs_discard_granularity;
> + sector_t discard_size = bdev_max_discard_sectors(bdev) << 9;
> int remainder;
>
> if (q->limits.discard_granularity > disk_conf->rs_discard_granularity)
> @@ -1463,8 +1465,8 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis
> remainder = disk_conf->rs_discard_granularity % q->limits.discard_granularity;
> disk_conf->rs_discard_granularity += remainder;
>
> - if (disk_conf->rs_discard_granularity > q->limits.max_discard_sectors << 9)
> - disk_conf->rs_discard_granularity = q->limits.max_discard_sectors << 9;
> + if (disk_conf->rs_discard_granularity > discard_size)
> + disk_conf->rs_discard_granularity = discard_size;
>
> if (disk_conf->rs_discard_granularity != orig_value)
> drbd_info(device, "rs_discard_granularity changed to %d\n",
> diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
> index 08da922f81d1d..8a4a47da56fe9 100644
> --- a/drivers/block/drbd/drbd_receiver.c
> +++ b/drivers/block/drbd/drbd_receiver.c
> @@ -1524,7 +1524,7 @@ int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, u
> granularity = max(q->limits.discard_granularity >> 9, 1U);
> alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
>
> - max_discard_sectors = min(q->limits.max_discard_sectors, (1U << 22));
> + max_discard_sectors = min(bdev_max_discard_sectors(bdev), (1U << 22));
> max_discard_sectors -= max_discard_sectors % granularity;
> if (unlikely(!max_discard_sectors))
> goto zero_out;
> @@ -1575,11 +1575,10 @@ int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, u
>
> static bool can_do_reliable_discards(struct drbd_device *device)
> {
> - struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
> struct disk_conf *dc;
> bool can_do;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(device->ldev->backing_bdev))
> return false;
>
> rcu_read_lock();
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 8d800d46e4985..4b919b75205a7 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -314,15 +314,12 @@ static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
>
> mode |= FALLOC_FL_KEEP_SIZE;
>
> - if (!blk_queue_discard(lo->lo_queue)) {
> - ret = -EOPNOTSUPP;
> - goto out;
> - }
> + if (!bdev_max_discard_sectors(lo->lo_device))
> + return -EOPNOTSUPP;
>
> ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
> if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
> - ret = -EIO;
> - out:
> + return -EIO;
> return ret;
> }
>
> diff --git a/drivers/block/rnbd/rnbd-srv-dev.h b/drivers/block/rnbd/rnbd-srv-dev.h
> index 2c3df02b5e8ec..1f7e1c8fd4d9b 100644
> --- a/drivers/block/rnbd/rnbd-srv-dev.h
> +++ b/drivers/block/rnbd/rnbd-srv-dev.h
> @@ -49,11 +49,7 @@ static inline int rnbd_dev_get_secure_discard(const struct rnbd_dev *dev)
>
> static inline int rnbd_dev_get_max_discard_sects(const struct rnbd_dev *dev)
> {
> - if (!blk_queue_discard(bdev_get_queue(dev->bdev)))
> - return 0;
> -
> - return blk_queue_get_max_sectors(bdev_get_queue(dev->bdev),
> - REQ_OP_DISCARD);
> + return bdev_max_discard_sectors(dev->bdev);
> }
>
> static inline int rnbd_dev_get_discard_granularity(const struct rnbd_dev *dev)
> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
> index 8b691fe50475f..83cd08041e6b3 100644
> --- a/drivers/block/xen-blkback/xenbus.c
> +++ b/drivers/block/xen-blkback/xenbus.c
> @@ -583,7 +583,7 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
> if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1))
> return;
>
> - if (blk_queue_discard(q)) {
> + if (bdev_max_discard_sectors(bdev)) {
> err = xenbus_printf(xbt, dev->nodename,
> "discard-granularity", "%u",
> q->limits.discard_granularity);
> diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
> index fdd0194f84dd0..e27f67f06a428 100644
> --- a/drivers/md/bcache/request.c
> +++ b/drivers/md/bcache/request.c
> @@ -1005,7 +1005,7 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s)
> bio_get(s->iop.bio);
>
> if (bio_op(bio) == REQ_OP_DISCARD &&
> - !blk_queue_discard(bdev_get_queue(dc->bdev)))
> + !bdev_max_discard_sectors(dc->bdev))
> goto insert_data;
>
> /* I/O request sent to backing device */
> @@ -1115,7 +1115,7 @@ static void detached_dev_do_request(struct bcache_device *d, struct bio *bio,
> bio->bi_private = ddip;
>
> if ((bio_op(bio) == REQ_OP_DISCARD) &&
> - !blk_queue_discard(bdev_get_queue(dc->bdev)))
> + !bdev_max_discard_sectors(dc->bdev))
> bio->bi_end_io(bio);
> else
> submit_bio_noacct(bio);
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index bf3de149d3c9f..296f200b2e208 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -2350,7 +2350,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
> ca->bdev->bd_holder = ca;
> ca->sb_disk = sb_disk;
>
> - if (blk_queue_discard(bdev_get_queue(bdev)))
> + if (bdev_max_discard_sectors((bdev)))
> ca->discard = CACHE_DISCARD(&ca->sb);
>
> ret = cache_alloc(ca);
> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
> index d1029d71ff3bc..c6f677059214d 100644
> --- a/drivers/md/bcache/sysfs.c
> +++ b/drivers/md/bcache/sysfs.c
> @@ -1151,7 +1151,7 @@ STORE(__bch_cache)
> if (attr == &sysfs_discard) {
> bool v = strtoul_or_return(buf);
>
> - if (blk_queue_discard(bdev_get_queue(ca->bdev)))
> + if (bdev_max_discard_sectors(ca->bdev))
> ca->discard = v;
>
> if (v != CACHE_DISCARD(&ca->sb)) {
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index 780a61bc6cc03..28c5de8eca4a0 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -3329,13 +3329,6 @@ static int cache_iterate_devices(struct dm_target *ti,
> return r;
> }
>
> -static bool origin_dev_supports_discard(struct block_device *origin_bdev)
> -{
> - struct request_queue *q = bdev_get_queue(origin_bdev);
> -
> - return blk_queue_discard(q);
> -}
> -
> /*
> * If discard_passdown was enabled verify that the origin device
> * supports discards. Disable discard_passdown if not.
> @@ -3349,7 +3342,7 @@ static void disable_passdown_if_not_supported(struct cache *cache)
> if (!cache->features.discard_passdown)
> return;
>
> - if (!origin_dev_supports_discard(origin_bdev))
> + if (!bdev_max_discard_sectors(origin_bdev))
> reason = "discard unsupported";
>
> else if (origin_limits->max_discard_sectors < cache->sectors_per_block)
> diff --git a/drivers/md/dm-clone-target.c b/drivers/md/dm-clone-target.c
> index 128316a73d016..811b0a5379d03 100644
> --- a/drivers/md/dm-clone-target.c
> +++ b/drivers/md/dm-clone-target.c
> @@ -2016,13 +2016,6 @@ static void clone_resume(struct dm_target *ti)
> do_waker(&clone->waker.work);
> }
>
> -static bool bdev_supports_discards(struct block_device *bdev)
> -{
> - struct request_queue *q = bdev_get_queue(bdev);
> -
> - return (q && blk_queue_discard(q));
> -}
> -
> /*
> * If discard_passdown was enabled verify that the destination device supports
> * discards. Disable discard_passdown if not.
> @@ -2036,7 +2029,7 @@ static void disable_passdown_if_not_supported(struct clone *clone)
> if (!test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags))
> return;
>
> - if (!bdev_supports_discards(dest_dev))
> + if (!bdev_max_discard_sectors(dest_dev))
> reason = "discard unsupported";
> else if (dest_limits->max_discard_sectors < clone->region_size)
> reason = "max discard sectors smaller than a region";
> diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
> index 5762366333a27..e4b95eaeec8c7 100644
> --- a/drivers/md/dm-io.c
> +++ b/drivers/md/dm-io.c
> @@ -311,7 +311,7 @@ static void do_region(int op, int op_flags, unsigned region,
> * Reject unsupported discard and write same requests.
> */
> if (op == REQ_OP_DISCARD)
> - special_cmd_max_sectors = q->limits.max_discard_sectors;
> + special_cmd_max_sectors = bdev_max_discard_sectors(where->bdev);
> else if (op == REQ_OP_WRITE_ZEROES)
> special_cmd_max_sectors = q->limits.max_write_zeroes_sectors;
> if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) &&
> diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
> index c9d036d6bb2ee..e194226c89e54 100644
> --- a/drivers/md/dm-log-writes.c
> +++ b/drivers/md/dm-log-writes.c
> @@ -866,9 +866,8 @@ static int log_writes_message(struct dm_target *ti, unsigned argc, char **argv,
> static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limits)
> {
> struct log_writes_c *lc = ti->private;
> - struct request_queue *q = bdev_get_queue(lc->dev->bdev);
>
> - if (!q || !blk_queue_discard(q)) {
> + if (!bdev_max_discard_sectors(lc->dev->bdev)) {
> lc->device_supports_discard = false;
> limits->discard_granularity = lc->sectorsize;
> limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index 2b26435a6946e..9526ccbedafba 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -2963,13 +2963,8 @@ static void configure_discard_support(struct raid_set *rs)
> raid456 = rs_is_raid456(rs);
>
> for (i = 0; i < rs->raid_disks; i++) {
> - struct request_queue *q;
> -
> - if (!rs->dev[i].rdev.bdev)
> - continue;
> -
> - q = bdev_get_queue(rs->dev[i].rdev.bdev);
> - if (!q || !blk_queue_discard(q))
> + if (!rs->dev[i].rdev.bdev ||
> + !bdev_max_discard_sectors(rs->dev[i].rdev.bdev))
> return;
>
> if (raid456) {
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index d46839faa0ca5..4297c38328a9b 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -1888,9 +1888,7 @@ static bool dm_table_supports_nowait(struct dm_table *t)
> static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
> sector_t start, sector_t len, void *data)
> {
> - struct request_queue *q = bdev_get_queue(dev->bdev);
> -
> - return !blk_queue_discard(q);
> + return !bdev_max_discard_sectors(dev->bdev);
> }
>
> static bool dm_table_supports_discards(struct dm_table *t)
> diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
> index 4d25d0e270313..cd333a3e4c33b 100644
> --- a/drivers/md/dm-thin.c
> +++ b/drivers/md/dm-thin.c
> @@ -2802,13 +2802,6 @@ static void requeue_bios(struct pool *pool)
> /*----------------------------------------------------------------
> * Binding of control targets to a pool object
> *--------------------------------------------------------------*/
> -static bool data_dev_supports_discard(struct pool_c *pt)
> -{
> - struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
> -
> - return blk_queue_discard(q);
> -}
> -
> static bool is_factor(sector_t block_size, uint32_t n)
> {
> return !sector_div(block_size, n);
> @@ -2828,7 +2821,7 @@ static void disable_passdown_if_not_supported(struct pool_c *pt)
> if (!pt->adjusted_pf.discard_passdown)
> return;
>
> - if (!data_dev_supports_discard(pt))
> + if (!bdev_max_discard_sectors(pt->data_dev->bdev))
> reason = "discard unsupported";
>
> else if (data_limits->max_discard_sectors < pool->sectors_per_block)
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 3c5fad7c4ee68..ba75933cc22ca 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -982,7 +982,7 @@ static void clone_endio(struct bio *bio)
>
> if (unlikely(error == BLK_STS_TARGET)) {
> if (bio_op(bio) == REQ_OP_DISCARD &&
> - !q->limits.max_discard_sectors)
> + !bdev_max_discard_sectors(bio->bi_bdev))
> disable_discard(md);
> else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
> !q->limits.max_write_zeroes_sectors)
> diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
> index 0f55b079371b1..4dd5afff72844 100644
> --- a/drivers/md/md-linear.c
> +++ b/drivers/md/md-linear.c
> @@ -97,7 +97,7 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
> conf->array_sectors += rdev->sectors;
> cnt++;
>
> - if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (bdev_max_discard_sectors(rdev->bdev))
> discard_supported = true;
> }
> if (cnt != raid_disks) {
> @@ -252,7 +252,7 @@ static bool linear_make_request(struct mddev *mddev, struct bio *bio)
> start_sector + data_offset;
>
> if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
> - !blk_queue_discard(bio->bi_bdev->bd_disk->queue))) {
> + !bdev_max_discard_sectors(bio->bi_bdev))) {
> /* Just ignore it */
> bio_endio(bio);
> } else {
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index b21e101183f44..02ac3ab213c72 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -412,7 +412,7 @@ static int raid0_run(struct mddev *mddev)
> rdev_for_each(rdev, mddev) {
> disk_stack_limits(mddev->gendisk, rdev->bdev,
> rdev->data_offset << 9);
> - if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (bdev_max_discard_sectors(rdev->bdev))
> discard_supported = true;
> }
> if (!discard_supported)
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index d81b896855f9f..39b9cb4d54ee0 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -802,7 +802,7 @@ static void flush_bio_list(struct r1conf *conf, struct bio *bio)
> if (test_bit(Faulty, &rdev->flags)) {
> bio_io_error(bio);
> } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
> - !blk_queue_discard(bio->bi_bdev->bd_disk->queue)))
> + !bdev_max_discard_sectors(bio->bi_bdev)))
> /* Just ignore it */
> bio_endio(bio);
> else
> @@ -1826,7 +1826,7 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> break;
> }
> }
> - if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (mddev->queue && bdev_max_discard_sectors(rdev->bdev))
> blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
> print_conf(conf);
> return err;
> @@ -3141,7 +3141,7 @@ static int raid1_run(struct mddev *mddev)
> continue;
> disk_stack_limits(mddev->gendisk, rdev->bdev,
> rdev->data_offset << 9);
> - if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (bdev_max_discard_sectors(rdev->bdev))
> discard_supported = true;
> }
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 7816c8b2e8087..eaa86c6a35a55 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -888,7 +888,7 @@ static void flush_pending_writes(struct r10conf *conf)
> if (test_bit(Faulty, &rdev->flags)) {
> bio_io_error(bio);
> } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
> - !blk_queue_discard(bio->bi_bdev->bd_disk->queue)))
> + !bdev_max_discard_sectors(bio->bi_bdev)))
> /* Just ignore it */
> bio_endio(bio);
> else
> @@ -1083,7 +1083,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
> if (test_bit(Faulty, &rdev->flags)) {
> bio_io_error(bio);
> } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
> - !blk_queue_discard(bio->bi_bdev->bd_disk->queue)))
> + !bdev_max_discard_sectors(bio->bi_bdev)))
> /* Just ignore it */
> bio_endio(bio);
> else
> @@ -2144,7 +2144,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> rcu_assign_pointer(p->rdev, rdev);
> break;
> }
> - if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (mddev->queue && bdev_max_discard_sectors(rdev->bdev))
> blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
>
> print_conf(conf);
> @@ -4141,7 +4141,7 @@ static int raid10_run(struct mddev *mddev)
>
> disk->head_position = 0;
>
> - if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
> + if (bdev_max_discard_sectors(rdev->bdev))
> discard_supported = true;
> first = 0;
> }
> diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
> index a7d50ff9020a8..c3cbf9a574a39 100644
> --- a/drivers/md/raid5-cache.c
> +++ b/drivers/md/raid5-cache.c
> @@ -1318,7 +1318,7 @@ static void r5l_write_super_and_discard_space(struct r5l_log *log,
>
> r5l_write_super(log, end);
>
> - if (!blk_queue_discard(bdev_get_queue(bdev)))
> + if (!bdev_max_discard_sectors(bdev))
> return;
>
> mddev = log->rdev->mddev;
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index 16e775bcf4a7c..7d510e4231713 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -829,9 +829,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
> }
>
> /*
> - * Check if the underlying struct block_device request_queue supports
> - * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
> - * in ATA and we need to set TPE=1
> + * Check if the underlying struct block_device request_queue supports disard.
> */
> bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
> struct block_device *bdev)
> @@ -839,11 +837,11 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
> struct request_queue *q = bdev_get_queue(bdev);
> int block_size = bdev_logical_block_size(bdev);
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(bdev))
> return false;
>
> attrib->max_unmap_lba_count =
> - q->limits.max_discard_sectors >> (ilog2(block_size) - 9);
> + bdev_max_discard_sectors(bdev) >> (ilog2(block_size) - 9);
> /*
> * Currently hardcoded to 1 in Linux/SCSI code..
> */
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index f477035a2ac23..efd8deb3ab7e8 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -1291,7 +1291,7 @@ static int do_discard_extent(struct btrfs_io_stripe *stripe, u64 *bytes)
> ret = btrfs_reset_device_zone(dev_replace->tgtdev, phys, len,
> &discarded);
> discarded += src_disc;
> - } else if (blk_queue_discard(bdev_get_queue(stripe->dev->bdev))) {
> + } else if (bdev_max_discard_sectors(stripe->dev->bdev)) {
> ret = btrfs_issue_discard(dev->bdev, phys, len, &discarded);
> } else {
> ret = 0;
> @@ -5987,7 +5987,7 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
> *trimmed = 0;
>
> /* Discard not supported = nothing to do. */
> - if (!blk_queue_discard(bdev_get_queue(device->bdev)))
> + if (!bdev_max_discard_sectors(device->bdev))
> return 0;
>
> /* Not writable = nothing to do. */
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 238cee5b5254d..fc7953755fd8b 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -501,7 +501,7 @@ static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
> if (!device->bdev)
> continue;
> q = bdev_get_queue(device->bdev);
> - if (blk_queue_discard(q)) {
> + if (bdev_max_discard_sectors(device->bdev)) {
> num_devices++;
> minlen = min_t(u64, q->limits.discard_granularity,
> minlen);
> diff --git a/fs/exfat/file.c b/fs/exfat/file.c
> index 2f51300592366..765e4f63dd18d 100644
> --- a/fs/exfat/file.c
> +++ b/fs/exfat/file.c
> @@ -358,7 +358,7 @@ static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(inode->i_sb->s_bdev))
> return -EOPNOTSUPP;
>
> if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
> diff --git a/fs/exfat/super.c b/fs/exfat/super.c
> index 8ca21e7917d16..be0788ecaf20e 100644
> --- a/fs/exfat/super.c
> +++ b/fs/exfat/super.c
> @@ -627,13 +627,9 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
> if (opts->allow_utime == (unsigned short)-1)
> opts->allow_utime = ~opts->fs_dmask & 0022;
>
> - if (opts->discard) {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> -
> - if (!blk_queue_discard(q)) {
> - exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
> - opts->discard = 0;
> - }
> + if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
> + exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
> + opts->discard = 0;
> }
>
> sb->s_flags |= SB_NODIRATIME;
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index 992229ca2d830..6e3b9eea126f4 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -1044,7 +1044,6 @@ static int ext4_ioctl_checkpoint(struct file *filp, unsigned long arg)
> __u32 flags = 0;
> unsigned int flush_flags = 0;
> struct super_block *sb = file_inode(filp)->i_sb;
> - struct request_queue *q;
>
> if (copy_from_user(&flags, (__u32 __user *)arg,
> sizeof(__u32)))
> @@ -1065,10 +1064,8 @@ static int ext4_ioctl_checkpoint(struct file *filp, unsigned long arg)
> if (flags & ~EXT4_IOC_CHECKPOINT_FLAG_VALID)
> return -EINVAL;
>
> - q = bdev_get_queue(EXT4_SB(sb)->s_journal->j_dev);
> - if (!q)
> - return -ENXIO;
> - if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) && !blk_queue_discard(q))
> + if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
> + !bdev_max_discard_sectors(EXT4_SB(sb)->s_journal->j_dev))
> return -EOPNOTSUPP;
>
> if (flags & EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN)
> @@ -1393,14 +1390,13 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>
> case FITRIM:
> {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> struct fstrim_range range;
> int ret = 0;
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(sb->s_bdev))
> return -EOPNOTSUPP;
>
> /*
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 81749eaddf4c1..93f4e4e9e2631 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5458,13 +5458,9 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> goto failed_mount9;
> }
>
> - if (test_opt(sb, DISCARD)) {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> - if (!blk_queue_discard(q))
> - ext4_msg(sb, KERN_WARNING,
> - "mounting with \"discard\" option, but "
> - "the device does not support discard");
> - }
> + if (test_opt(sb, DISCARD) && !bdev_max_discard_sectors(sb->s_bdev))
> + ext4_msg(sb, KERN_WARNING,
> + "mounting with \"discard\" option, but the device does not support discard");
>
> if (es->s_error_count)
> mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index cd1e65bcf0b04..0ea9a5fa7c1dd 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4381,8 +4381,7 @@ static inline bool f2fs_hw_should_discard(struct f2fs_sb_info *sbi)
>
> static inline bool f2fs_bdev_support_discard(struct block_device *bdev)
> {
> - return blk_queue_discard(bdev_get_queue(bdev)) ||
> - bdev_is_zoned(bdev);
> + return bdev_max_discard_sectors(bdev) || bdev_is_zoned(bdev);
> }
>
> static inline bool f2fs_hw_support_discard(struct f2fs_sb_info *sbi)
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 22dfeb9915290..71f09adbcba86 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1196,9 +1196,8 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> unsigned int *issued)
> {
> struct block_device *bdev = dc->bdev;
> - struct request_queue *q = bdev_get_queue(bdev);
> unsigned int max_discard_blocks =
> - SECTOR_TO_BLOCK(q->limits.max_discard_sectors);
> + SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> &(dcc->fstrim_list) : &(dcc->wait_list);
> @@ -1375,9 +1374,8 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
> struct discard_cmd *dc;
> struct discard_info di = {0};
> struct rb_node **insert_p = NULL, *insert_parent = NULL;
> - struct request_queue *q = bdev_get_queue(bdev);
> unsigned int max_discard_blocks =
> - SECTOR_TO_BLOCK(q->limits.max_discard_sectors);
> + SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
> block_t end = lstart + len;
>
> dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
> diff --git a/fs/fat/file.c b/fs/fat/file.c
> index a5a309fcc7faf..e4c7d10e80129 100644
> --- a/fs/fat/file.c
> +++ b/fs/fat/file.c
> @@ -133,7 +133,7 @@ static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(sb->s_bdev))
> return -EOPNOTSUPP;
>
> user_range = (struct fstrim_range __user *)arg;
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index bf6051bdf1d1d..3d1afb95a925a 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -1872,13 +1872,9 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
> goto out_fail;
> }
>
> - if (sbi->options.discard) {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> - if (!blk_queue_discard(q))
> - fat_msg(sb, KERN_WARNING,
> - "mounting with \"discard\" option, but "
> - "the device does not support discard");
> - }
> + if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
> + fat_msg(sb, KERN_WARNING,
> + "mounting with \"discard\" option, but the device does not support discard");
>
> fat_set_state(sb, 1, 0);
> return 0;
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 801ad9f4f2bef..7f20ac9133bc6 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -1405,7 +1405,7 @@ int gfs2_fitrim(struct file *filp, void __user *argp)
> if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
> return -EROFS;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(sdp->sd_vfs->s_bdev))
> return -EOPNOTSUPP;
>
> if (copy_from_user(&r, argp, sizeof(r)))
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index fcacafa4510d1..19d226cd4ff4d 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1762,7 +1762,6 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
> unsigned long block, log_offset; /* logical */
> unsigned long long phys_block, block_start, block_stop; /* physical */
> loff_t byte_start, byte_stop, byte_count;
> - struct request_queue *q = bdev_get_queue(journal->j_dev);
>
> /* flags must be set to either discard or zeroout */
> if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
> @@ -1770,10 +1769,8 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
> (flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
> return -EINVAL;
>
> - if (!q)
> - return -ENXIO;
> -
> - if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) && !blk_queue_discard(q))
> + if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
> + !bdev_max_discard_sectors(journal->j_dev))
> return -EOPNOTSUPP;
>
> /*
> diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
> index 03a845ab4f009..357ae6e5c36ec 100644
> --- a/fs/jfs/ioctl.c
> +++ b/fs/jfs/ioctl.c
> @@ -117,7 +117,7 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q)) {
> + if (!bdev_max_discard_sectors(sb->s_bdev)) {
> jfs_warn("FITRIM not supported on device");
> return -EOPNOTSUPP;
> }
> diff --git a/fs/jfs/super.c b/fs/jfs/super.c
> index f1a13a74cddf3..85d4f44f2ac4d 100644
> --- a/fs/jfs/super.c
> +++ b/fs/jfs/super.c
> @@ -372,19 +372,16 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
> }
>
> case Opt_discard:
> - {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> /* if set to 1, even copying files will cause
> * trimming :O
> * -> user has more control over the online trimming
> */
> sbi->minblks_trim = 64;
> - if (blk_queue_discard(q))
> + if (bdev_max_discard_sectors(sb->s_bdev))
> *flag |= JFS_DISCARD;
> else
> pr_err("JFS: discard option not supported on device\n");
> break;
> - }
>
> case Opt_nodiscard:
> *flag &= ~JFS_DISCARD;
> @@ -392,10 +389,9 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
>
> case Opt_discard_minblk:
> {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> char *minblks_trim = args[0].from;
> int rc;
> - if (blk_queue_discard(q)) {
> + if (bdev_max_discard_sectors(sb->s_bdev)) {
> *flag |= JFS_DISCARD;
> rc = kstrtouint(minblks_trim, 0,
> &sbi->minblks_trim);
> diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
> index fec194a666f4b..52b73f558fcb1 100644
> --- a/fs/nilfs2/ioctl.c
> +++ b/fs/nilfs2/ioctl.c
> @@ -1059,7 +1059,7 @@ static int nilfs_ioctl_trim_fs(struct inode *inode, void __user *argp)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(nilfs->ns_bdev))
> return -EOPNOTSUPP;
>
> if (copy_from_user(&range, argp, sizeof(range)))
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index 787b53b984ee1..e763236169331 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -28,7 +28,7 @@ static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(sbi->sb->s_bdev))
> return -EOPNOTSUPP;
>
> user_range = (struct fstrim_range __user *)arg;
> diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
> index cd30e81abbce0..c734085bcce4a 100644
> --- a/fs/ntfs3/super.c
> +++ b/fs/ntfs3/super.c
> @@ -913,7 +913,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
> }
>
> rq = bdev_get_queue(bdev);
> - if (blk_queue_discard(rq) && rq->limits.discard_granularity) {
> + if (bdev_max_discard_sectors(bdev) && rq->limits.discard_granularity) {
> sbi->discard_granularity = rq->limits.discard_granularity;
> sbi->discard_granularity_mask_inv =
> ~(u64)(sbi->discard_granularity - 1);
> diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
> index f59461d85da45..9b78ef103ada6 100644
> --- a/fs/ocfs2/ioctl.c
> +++ b/fs/ocfs2/ioctl.c
> @@ -910,7 +910,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(sb->s_bdev))
> return -EOPNOTSUPP;
>
> if (copy_from_user(&range, argp, sizeof(range)))
> diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
> index 0191de8ce9ced..a4e6609d616b7 100644
> --- a/fs/xfs/xfs_discard.c
> +++ b/fs/xfs/xfs_discard.c
> @@ -162,7 +162,7 @@ xfs_ioc_trim(
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
> - if (!blk_queue_discard(q))
> + if (!bdev_max_discard_sectors(mp->m_ddev_targp->bt_bdev))
> return -EOPNOTSUPP;
>
> /*
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 54be9d64093ed..a276b8111f636 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1608,14 +1608,10 @@ xfs_fs_fill_super(.
> goto out_filestream_unmount;
> }>

> - if (xfs_has_discard(mp)) {
> - struct request_queue *q = bdev_get_queue(sb->s_bdev);
> -
> - if (!blk_queue_discard(q)) {
> - xfs_warn(mp, "mounting with \"discard\" option, but "
> - "the device does not support discard");
> - mp->m_features &= ~XFS_FEAT_DISCARD;
> - }
> + if (xfs_has_discard(mp) && !bdev_max_discard_sectors(sb->s_bdev)) {
> + xfs_warn(mp,
> + "mounting with \"discard\" option, but the device does not support discard");
> + mp->m_features &= ~XFS_FEAT_DISCARD;
> }
>
> if (xfs_has_reflink(mp)) {
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 34b1cfd067421..ce16247d3afab 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1254,6 +1254,11 @@ bdev_zone_write_granularity(struct block_device *bdev)
> int bdev_alignment_offset(struct block_device *bdev);
> unsigned int bdev_discard_alignment(struct block_device *bdev);
>
> +static inline unsigned int bdev_max_discard_sectors(struct block_device *bdev)
> +{
> + return bdev_get_queue(bdev)->limits.max_discard_sectors;
> +}
> +

So this patch replaces checking for blk_queue_discard(q) with checking
whether bdev_max_discard_sectors() is nonzero. That doesn't seem to be
equivalent for callers like drivers/md/raid0.c:raid0_run() which clear
the QUEUE_FLAG_DISCARD flag without zeroing out max_discard_sectors,
for example. Should a test for the QUEUE_FLAG_DISCARD flag be added
here?

If I'm misreading things, could you please document that
bdev_max_discard_sectors() != 0 implies that discard is supported?

Thanks,
Andreas

> static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
> {
> struct request_queue *q = bdev_get_queue(bdev);
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 4069f17a82c8e..5d9cedf9e7b84 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -2957,20 +2957,6 @@ static int setup_swap_map_and_extents(struct swap_info_struct *p,
> return nr_extents;
> }
>
> -/*
> - * Helper to sys_swapon determining if a given swap
> - * backing device queue supports DISCARD operations.
> - */
> -static bool swap_discardable(struct swap_info_struct *si)
> -{
> - struct request_queue *q = bdev_get_queue(si->bdev);
> -
> - if (!blk_queue_discard(q))
> - return false;
> -
> - return true;
> -}
> -
> SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
> {
> struct swap_info_struct *p;
> @@ -3132,7 +3118,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
> sizeof(long),
> GFP_KERNEL);
>
> - if (p->bdev && (swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
> + if ((swap_flags & SWAP_FLAG_DISCARD) &&
> + p->bdev && bdev_max_discard_sectors(p->bdev)) {
> /*
> * When discard is enabled for swap with no particular
> * policy flagged, we set all swap discard flags here in
> --
> 2.30.2
>