dax: remove bdev_dax_supported

All callers already have a dax_device obtained from fs_dax_get_by_bdev
at hand, so just pass that to dax_supported() insted of doing another
lookup.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20210826135510.6293-10-hch@lst.deSigned-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dax/super.c

@@ -220,47 +220,7 @@ bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
 }
 EXPORT_SYMBOL_GPL(dax_supported);
 #endif /* CONFIG_FS_DAX */
-
-/**
- * __bdev_dax_supported() - Check if the device supports dax for filesystem
- * @bdev: block device to check
- * @blocksize: The block size of the device
- *
- * This is a library function for filesystems to check if the block device
- * can be mounted with dax option.
- *
- * Return: true if supported, false if unsupported
- */
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
-{
-	struct dax_device *dax_dev;
-	struct request_queue *q;
-	char buf[BDEVNAME_SIZE];
-	bool ret;
-
-	q = bdev_get_queue(bdev);
-	if (!q || !blk_queue_dax(q)) {
-		pr_debug("%s: error: request queue doesn't support dax\n",
-				bdevname(bdev, buf));
-		return false;
-	}
-
-	dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
-	if (!dax_dev) {
-		pr_debug("%s: error: device does not support dax\n",
-				bdevname(bdev, buf));
-		return false;
-	}
-
-	ret = dax_supported(dax_dev, bdev, blocksize, 0,
-			i_size_read(bdev->bd_inode) / 512);
-
-	put_dax(dax_dev);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(__bdev_dax_supported);
-#endif
+#endif /* CONFIG_BLOCK */
 
 enum dax_device_flags {
 	/* !alive + rcu grace period == no new operations / mappings */

fs/ext2/super.c

@@ -949,7 +949,8 @@ 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 (!bdev_dax_supported(sb->s_bdev, blocksize)) {
+		if (!dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
+				bdev_nr_sectors(sb->s_bdev))) {
 			ext2_msg(sb, KERN_ERR,
 				"DAX unsupported by block device. Turning off DAX.");
 			clear_opt(sbi->s_mount_opt, DAX);

fs/ext4/super.c

@@ -4435,7 +4435,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
-	if (bdev_dax_supported(sb->s_bdev, blocksize))
+	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 (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {

fs/xfs/xfs_super.c

@@ -319,7 +319,8 @@ xfs_buftarg_is_dax(
 	struct super_block	*sb,
 	struct xfs_buftarg	*bt)
 {
-	return bdev_dax_supported(bt->bt_bdev, sb->s_blocksize);
+	return dax_supported(bt->bt_daxdev, bt->bt_bdev, sb->s_blocksize, 0,
+			bdev_nr_sectors(bt->bt_bdev));
 }
 
 STATIC int

include/linux/dax.h

@@ -109,12 +109,6 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 struct writeback_control;
 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
 #if IS_ENABLED(CONFIG_FS_DAX)
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
-static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
-{
-	return __bdev_dax_supported(bdev, blocksize);
-}
-
 bool generic_fsdax_supported(struct dax_device *dax_dev,
 		struct block_device *bdev, int blocksize, sector_t start,
 		sector_t sectors);
@@ -136,12 +130,6 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t st
 dax_entry_t dax_lock_page(struct page *page);
 void dax_unlock_page(struct page *page, dax_entry_t cookie);
 #else
-static inline bool bdev_dax_supported(struct block_device *bdev,
-		int blocksize)
-{
-	return false;
-}
-
 #define generic_fsdax_supported		NULL
 
 static inline bool dax_supported(struct dax_device *dax_dev,