Re: [PATCH 08/29] dax: remove dax_capable

Dan Williams
2021-11-23T03:58:32Z

On Tue, Nov 9, 2021 at 12:33 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Just open code the block size and dax_dev == NULL checks in the callers.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Mike Snitzer <snitzer@redhat.com>

You dropped Gao Xiang's reviewed-by:

https://lore.kernel.org/r/YW1nrxmaw5CfFXBb@B-P7TQMD6M-0146.local

...and Darrick's

https://lore.kernel.org/r/20211019154447.GL24282@magnolia

...which had a few more review comments below, otherwise you can also add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

> ---
> drivers/dax/super.c | 36 ------------------------------------
> drivers/md/dm-table.c | 22 +++++++++++-----------
> drivers/md/dm.c | 21 ---------------------
> drivers/md/dm.h | 4 ----
> drivers/nvdimm/pmem.c | 1 -
> drivers/s390/block/dcssblk.c | 1 -
> fs/erofs/super.c | 11 +++++++----
> fs/ext2/super.c | 6 ++++--
> fs/ext4/super.c | 9 ++++++---
> fs/xfs/xfs_super.c | 21 ++++++++-------------
> include/linux/dax.h | 14 --------------
> 11 files changed, 36 insertions(+), 110 deletions(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index 482fe775324a4..803942586d1b6 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -108,42 +108,6 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
> return dax_dev;
> }
> EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
> -
> -bool generic_fsdax_supported(struct dax_device *dax_dev,
> - struct block_device *bdev, int blocksize, sector_t start,
> - sector_t sectors)
> -{
> - if (blocksize != PAGE_SIZE) {
> - pr_info("%pg: error: unsupported blocksize for dax\n", bdev);
> - return false;
> - }
> -
> - if (!dax_dev) {
> - pr_debug("%pg: error: dax unsupported by block device\n", bdev);
> - return false;
> - }
> -
> - return true;
> -}
> -EXPORT_SYMBOL_GPL(generic_fsdax_supported);
> -
> -bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
> - int blocksize, sector_t start, sector_t len)
> -{
> - bool ret = false;
> - int id;
> -
> - if (!dax_dev)
> - return false;
> -
> - id = dax_read_lock();
> - if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)
> - ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,
> - start, len);
> - dax_read_unlock(id);
> - return ret;
> -}
> -EXPORT_SYMBOL_GPL(dax_supported);
> #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
>
> enum dax_device_flags {
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index bcddc5effd155..f4915a7d5dc84 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -806,12 +806,14 @@ void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type)
> EXPORT_SYMBOL_GPL(dm_table_set_type);
>
> /* validate the dax capability of the target device span */
> -int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
> +static int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
> sector_t start, sector_t len, void *data)
> {
> - int blocksize = *(int *) data;
> + if (dev->dax_dev)
> + return false;
>
> - return !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
> + DMDEBUG("%pg: error: dax unsupported by block device", dev->bdev);
> + return true;
> }
>
> /* Check devices support synchronous DAX */
> @@ -821,8 +823,8 @@ static int device_not_dax_synchronous_capable(struct dm_target *ti, struct dm_de
> return !dev->dax_dev || !dax_synchronous(dev->dax_dev);
> }
>
> -bool dm_table_supports_dax(struct dm_table *t,
> - iterate_devices_callout_fn iterate_fn, int *blocksize)
> +static bool dm_table_supports_dax(struct dm_table *t,
> + iterate_devices_callout_fn iterate_fn)
> {
> struct dm_target *ti;
> unsigned i;
> @@ -835,7 +837,7 @@ bool dm_table_supports_dax(struct dm_table *t,
> return false;
>
> if (!ti->type->iterate_devices ||
> - ti->type->iterate_devices(ti, iterate_fn, blocksize))
> + ti->type->iterate_devices(ti, iterate_fn, NULL))
> return false;
> }
>
> @@ -862,7 +864,6 @@ static int dm_table_determine_type(struct dm_table *t)
> struct dm_target *tgt;
> struct list_head *devices = dm_table_get_devices(t);
> enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
> - int page_size = PAGE_SIZE;
>
> if (t->type != DM_TYPE_NONE) {
> /* target already set the table's type */
> @@ -906,7 +907,7 @@ static int dm_table_determine_type(struct dm_table *t)
> verify_bio_based:
> /* We must use this table as bio-based */
> t->type = DM_TYPE_BIO_BASED;
> - if (dm_table_supports_dax(t, device_not_dax_capable, &page_size) ||
> + if (dm_table_supports_dax(t, device_not_dax_capable) ||
> (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) {
> t->type = DM_TYPE_DAX_BIO_BASED;
> }
> @@ -1976,7 +1977,6 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
> struct queue_limits *limits)
> {
> bool wc = false, fua = false;
> - int page_size = PAGE_SIZE;
> int r;
>
> /*
> @@ -2010,9 +2010,9 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
> }
> blk_queue_write_cache(q, wc, fua);
>
> - if (dm_table_supports_dax(t, device_not_dax_capable, &page_size)) {
> + if (dm_table_supports_dax(t, device_not_dax_capable)) {
> blk_queue_flag_set(QUEUE_FLAG_DAX, q);
> - if (dm_table_supports_dax(t, device_not_dax_synchronous_capable, NULL))
> + if (dm_table_supports_dax(t, device_not_dax_synchronous_capable))
> set_dax_synchronous(t->md->dax_dev);
> }
> else
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 782a076f61f81..282008afc465f 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1027,26 +1027,6 @@ static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
> return ret;
> }
>
> -static bool dm_dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
> - int blocksize, sector_t start, sector_t len)
> -{
> - struct mapped_device *md = dax_get_private(dax_dev);
> - struct dm_table *map;
> - bool ret = false;
> - int srcu_idx;
> -
> - map = dm_get_live_table(md, &srcu_idx);
> - if (!map)
> - goto out;
> -
> - ret = dm_table_supports_dax(map, device_not_dax_capable, &blocksize);
> -
> -out:
> - dm_put_live_table(md, srcu_idx);
> -
> - return ret;
> -}
> -
> static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
> void *addr, size_t bytes, struct iov_iter *i)
> {
> @@ -3052,7 +3032,6 @@ static const struct block_device_operations dm_rq_blk_dops = {
>
> static const struct dax_operations dm_dax_ops = {
> .direct_access = dm_dax_direct_access,
> - .dax_supported = dm_dax_supported,
> .copy_from_iter = dm_dax_copy_from_iter,
> .copy_to_iter = dm_dax_copy_to_iter,
> .zero_page_range = dm_dax_zero_page_range,
> diff --git a/drivers/md/dm.h b/drivers/md/dm.h
> index 742d9c80efe19..9013dc1a7b002 100644
> --- a/drivers/md/dm.h
> +++ b/drivers/md/dm.h
> @@ -73,10 +73,6 @@ bool dm_table_bio_based(struct dm_table *t);
> bool dm_table_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);
> -bool dm_table_supports_dax(struct dm_table *t, iterate_devices_callout_fn fn,
> - int *blocksize);
> -int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
> - sector_t start, sector_t len, void *data);
>
> void dm_lock_md_type(struct mapped_device *md);
> void dm_unlock_md_type(struct mapped_device *md);
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 8783ad7370856..0d66339875523 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -321,7 +321,6 @@ static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
>
> static const struct dax_operations pmem_dax_ops = {
> .direct_access = pmem_dax_direct_access,
> - .dax_supported = generic_fsdax_supported,
> .copy_from_iter = pmem_copy_from_iter,
> .copy_to_iter = pmem_copy_to_iter,
> .zero_page_range = pmem_dax_zero_page_range,
> diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
> index 657e492f2bc26..e65e83764d1ce 100644
> --- a/drivers/s390/block/dcssblk.c
> +++ b/drivers/s390/block/dcssblk.c
> @@ -72,7 +72,6 @@ static int dcssblk_dax_zero_page_range(struct dax_device *dax_dev,
>
> static const struct dax_operations dcssblk_dax_ops = {
> .direct_access = dcssblk_dax_direct_access,
> - .dax_supported = generic_fsdax_supported,
> .copy_from_iter = dcssblk_dax_copy_from_iter,
> .copy_to_iter = dcssblk_dax_copy_to_iter,
> .zero_page_range = dcssblk_dax_zero_page_range,
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 6a969b1e0ee6b..0aed886473c8d 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -652,10 +652,13 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
> if (err)
> return err;
>
> - if (test_opt(&sbi->opt, DAX_ALWAYS) &&
> - !dax_supported(sbi->dax_dev, sb->s_bdev, EROFS_BLKSIZ, 0, bdev_nr_sectors(sb->s_bdev))) {
> - errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
> - clear_opt(&sbi->opt, DAX_ALWAYS);
> + if (test_opt(&sbi->opt, DAX_ALWAYS)) {
> + BUILD_BUG_ON(EROFS_BLKSIZ != PAGE_SIZE);
> +
> + if (!sbi->dax_dev) {
> + errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
> + clear_opt(&sbi->opt, DAX_ALWAYS);
> + }
> }
> sb->s_flags |= SB_RDONLY | SB_NOATIME;
> sb->s_maxbytes = MAX_LFS_FILESIZE;
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index d8d580b609baa..a964066a80aa7 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -946,11 +946,13 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
>
> if (test_opt(sb, DAX)) {
> - if (!dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
> - bdev_nr_sectors(sb->s_bdev))) {
> + if (!dax_dev) {
> ext2_msg(sb, KERN_ERR,
> "DAX unsupported by block device. Turning off DAX.");
> clear_opt(sbi->s_mount_opt, DAX);
> + } else if (blocksize != PAGE_SIZE) {
> + ext2_msg(sb, KERN_ERR, "unsupported blocksize for DAX\n");

Per Darrick, drop the '\n".

> + clear_opt(sbi->s_mount_opt, DAX);
> }
> }
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index a320c54202d95..eb4df43abd76e 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4300,9 +4300,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
> goto failed_mount;
> }
>
> - if (dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
> - bdev_nr_sectors(sb->s_bdev)))
> - set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
> + if (dax_dev) {
> + if (blocksize == PAGE_SIZE)
> + set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
> + else
> + ext4_msg(sb, KERN_ERR, "unsupported blocksize for DAX\n");

...another one.

> + }
>
> if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {
> if (ext4_has_feature_inline_data(sb)) {
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 875fd3151d6c9..3a45d5caa28d5 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -331,28 +331,23 @@ xfs_set_inode_alloc(
> return xfs_is_inode32(mp) ? maxagi : agcount;
> }
>
> -static bool
> -xfs_buftarg_is_dax(
> - struct super_block *sb,
> - struct xfs_buftarg *bt)
> -{
> - return dax_supported(bt->bt_daxdev, bt->bt_bdev, sb->s_blocksize, 0,
> - bdev_nr_sectors(bt->bt_bdev));
> -}
> -
> static int
> xfs_setup_dax_always(
> struct xfs_mount *mp)
> {
> - struct super_block *sb = mp->m_super;
> -
> - if (!xfs_buftarg_is_dax(sb, mp->m_ddev_targp) &&
> - (!mp->m_rtdev_targp || !xfs_buftarg_is_dax(sb, mp->m_rtdev_targp))) {
> + if (!mp->m_ddev_targp->bt_daxdev &&
> + (!mp->m_rtdev_targp || !mp->m_rtdev_targp->bt_daxdev)) {
> xfs_alert(mp,
> "DAX unsupported by block device. Turning off DAX.");
> goto disable_dax;
> }
>
> + if (mp->m_super->s_blocksize != PAGE_SIZE) {
> + xfs_alert(mp,
> + "DAX not supported for blocksize. Turning off DAX.\n");

...and one more

> + goto disable_dax;
> + }
> +
> if (xfs_has_reflink(mp)) {
> xfs_alert(mp, "DAX and reflink cannot be used together!");
> return -EINVAL;
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index e2e9a67004cbd..439c3c70e347b 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -111,12 +111,6 @@ int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
> #if IS_ENABLED(CONFIG_FS_DAX)
> int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
> void dax_remove_host(struct gendisk *disk);
> -bool generic_fsdax_supported(struct dax_device *dax_dev,
> - struct block_device *bdev, int blocksize, sector_t start,
> - sector_t sectors);
> -
> -bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
> - int blocksize, sector_t start, sector_t len);
>
> static inline void fs_put_dax(struct dax_device *dax_dev)
> {
> @@ -139,14 +133,6 @@ static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
> static inline void dax_remove_host(struct gendisk *disk)
> {
> }
> -#define generic_fsdax_supported NULL
> -
> -static inline bool dax_supported(struct dax_device *dax_dev,
> - struct block_device *bdev, int blocksize, sector_t start,
> - sector_t len)
> -{
> - return false;
> -}
>
> static inline void fs_put_dax(struct dax_device *dax_dev)
> {
> --
> 2.30.2
>