Re: [PATCH v4 1/3] fs: allow per-device dax status checking for filesystems

Christoph Hellwig
2018-02-15T17:52:41Z

> /**
> - * __bdev_dax_supported() - Check if the device supports dax for filesystem
> + * bdev_dax_supported() - Check if the device supports dax for filesystem
> * @sb: The superblock of the device
> + * @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
> @@ -82,9 +83,9 @@ EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
> *
> * Return: negative errno if unsupported, 0 if supported.
> */
> -int __bdev_dax_supported(struct super_block *sb, int blocksize)
> +int bdev_dax_supported(struct super_block *sb, struct block_device *bdev,
> + int blocksize)
> {
> - struct block_device *bdev = sb->s_bdev;
> struct dax_device *dax_dev;
> pgoff_t pgoff;
> int err, id;

This now only uses sb for sb->s_id. It might be better to use bdevname
to print the device name and don't bother passing a sb at all.