On Mon, Nov 29, 2021 at 11:21:59AM +0100, Christoph Hellwig wrote:
> Prepare for the removal of the block_device from the DAX I/O path by
> returning the partition offset from fs_dax_get_by_bdev so that the file
> systems have it at hand for use during I/O.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> drivers/dax/super.c | 9 ++++++---
> drivers/md/dm.c | 4 ++--
> fs/erofs/internal.h | 2 ++
> fs/erofs/super.c | 4 ++--
> fs/ext2/ext2.h | 1 +
> fs/ext2/super.c | 2 +-
> fs/ext4/ext4.h | 1 +
> fs/ext4/super.c | 2 +-
> fs/xfs/xfs_buf.c | 2 +-
> fs/xfs/xfs_buf.h | 1 +
> include/linux/dax.h | 6 ++++--
> 11 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index 45d931aefd063..e7152a6c4cc40 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -69,17 +69,20 @@ EXPORT_SYMBOL_GPL(dax_remove_host);
> /**
> * fs_dax_get_by_bdev() - temporary lookup mechanism for filesystem-dax
> * @bdev: block device to find a dax_device for
> + * @start_off: returns the byte offset into the dax_device that @bdev starts
> */
> -struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
> +struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off)
> {
> struct dax_device *dax_dev;
> + u64 part_size;
> int id;
>
> if (!blk_queue_dax(bdev->bd_disk->queue))
> return NULL;
>
> - if ((get_start_sect(bdev) * SECTOR_SIZE) % PAGE_SIZE ||
> - (bdev_nr_sectors(bdev) * SECTOR_SIZE) % PAGE_SIZE) {
> + *start_off = get_start_sect(bdev) * SECTOR_SIZE;
> + part_size = bdev_nr_sectors(bdev) * SECTOR_SIZE;
> + if (*start_off % PAGE_SIZE || part_size % PAGE_SIZE) {
> pr_info("%pg: error: unaligned partition for dax\n", bdev);
> return NULL;
> }
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 4eba27e75c230..4e997c02bb0a0 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -637,7 +637,7 @@ static int open_table_device(struct table_device *td, dev_t dev,
> struct mapped_device *md)
> {
> struct block_device *bdev;
> -
> + u64 part_off;
> int r;
>
> BUG_ON(td->dm_dev.bdev);
> @@ -653,7 +653,7 @@ static int open_table_device(struct table_device *td, dev_t dev,
> }
>
> td->dm_dev.bdev = bdev;
> - td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev);
> + td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off);
> return 0;
> }
>
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 3265688af7f9f..c1e65346e9f15 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -51,6 +51,7 @@ struct erofs_device_info {
> char *path;
> struct block_device *bdev;
> struct dax_device *dax_dev;
> + u64 dax_part_off;
>
> u32 blocks;
> u32 mapped_blkaddr;
> @@ -109,6 +110,7 @@ struct erofs_sb_info {
> #endif /* CONFIG_EROFS_FS_ZIP */
> struct erofs_dev_context *devs;
> struct dax_device *dax_dev;
> + u64 dax_part_off;
> u64 total_blocks;
> u32 primarydevice_blocks;
>
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 0aed886473c8d..71efce16024d9 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -312,7 +312,7 @@ static int erofs_init_devices(struct super_block *sb,
> goto err_out;
> }
> dif->bdev = bdev;
> - dif->dax_dev = fs_dax_get_by_bdev(bdev);
> + dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off);
> dif->blocks = le32_to_cpu(dis->blocks);
> dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
> sbi->total_blocks += dif->blocks;
> @@ -644,7 +644,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>
> sb->s_fs_info = sbi;
> sbi->opt = ctx->opt;
> - sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
> + sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->dax_part_off);
> sbi->devs = ctx->devs;
> ctx->devs = NULL;
>
> diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
> index 3be9dd6412b78..d4f306aa5aceb 100644
> --- a/fs/ext2/ext2.h
> +++ b/fs/ext2/ext2.h
> @@ -118,6 +118,7 @@ struct ext2_sb_info {
> spinlock_t s_lock;
> struct mb_cache *s_ea_block_cache;
> struct dax_device *s_daxdev;
> + u64 s_dax_part_off;
> };
>
> static inline spinlock_t *
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 7e23482862e69..94f1fbd7d3ac2 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -831,7 +831,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> }
> sb->s_fs_info = sbi;
> sbi->s_sb_block = sb_block;
> - sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev);
> + sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->s_dax_part_off);
>
> spin_lock_init(&sbi->s_lock);
> ret = -EINVAL;
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 404dd50856e5d..9cc55bcda6ba4 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1697,6 +1697,7 @@ struct ext4_sb_info {
> */
> struct percpu_rw_semaphore s_writepages_rwsem;
> struct dax_device *s_daxdev;
> + u64 s_dax_part_off;
> #ifdef CONFIG_EXT4_DEBUG
> unsigned long s_simulate_fail;
> #endif
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 8d7e3449c6472..56228e33e52a2 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -3913,7 +3913,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
> if (!sbi->s_blockgroup_lock)
> goto out_free_base;
>
> - sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev);
> + sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->s_dax_part_off);
> sb->s_fs_info = sbi;
> sbi->s_sb = sb;
> sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 4d4553ffa7050..bbb0fbd34e649 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1945,7 +1945,7 @@ xfs_alloc_buftarg(
> btp->bt_mount = mp;
> btp->bt_dev = bdev->bd_dev;
> btp->bt_bdev = bdev;
> - btp->bt_daxdev = fs_dax_get_by_bdev(bdev);
> + btp->bt_daxdev = fs_dax_get_by_bdev(bdev, &btp->bt_dax_part_off);
>
> /*
> * Buffer IO error rate limiting. Limit it to no more than 10 messages
> diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
> index bd7f709f0d232..edcb6254fa6a8 100644
> --- a/fs/xfs/xfs_buf.h
> +++ b/fs/xfs/xfs_buf.h
> @@ -89,6 +89,7 @@ typedef struct xfs_buftarg {
> dev_t bt_dev;
> struct block_device *bt_bdev;
> struct dax_device *bt_daxdev;
> + u64 bt_dax_part_off;
> struct xfs_mount *bt_mount;
> unsigned int bt_meta_sectorsize;
> size_t bt_meta_sectormask;
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index b79036743e7fa..f6f353382cc90 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -117,7 +117,8 @@ static inline void fs_put_dax(struct dax_device *dax_dev)
> put_dax(dax_dev);
> }
>
> -struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
> +struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
> + u64 *start_off);
> int dax_writeback_mapping_range(struct address_space *mapping,
> struct dax_device *dax_dev, struct writeback_control *wbc);
>
> @@ -138,7 +139,8 @@ static inline void fs_put_dax(struct dax_device *dax_dev)
> {
> }
>
> -static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
> +static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
> + u64 *start_off)
> {
> return NULL;
> }
> --
> 2.30.2
>
