dax: remove dax_capable

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>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-9-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

4 files changed, 25 insertions, 22 deletions

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 6a969b1e0ee6..0aed886473c8 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 d8d580b609ba..a964066a80aa 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");
+			clear_opt(sbi->s_mount_opt, DAX);
 		}
 	}
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4e33b5eca694..fd3d68f10ee5 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4299,9 +4299,12 @@ 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");
+	}
 
 	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 875fd3151d6c..c4297206f483 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.");
+		goto disable_dax;
+	}
+
 	if (xfs_has_reflink(mp)) {
 		xfs_alert(mp, "DAX and reflink cannot be used together!");
 		return -EINVAL;