Re: [PATCH v4 6/6] block: Update blkdev_dax_capable() for consistency

[Jan Kara]

On Tue 10-05-16 10:23:57, Toshi Kani wrote:
> blkdev_dax_capable() is similar to bdev_dax_supported(), but needs
> to remain as a separate interface for checking dax capability of
> a raw block device.
> 
> Rename and relocate blkdev_dax_capable() to keep them maintained
> consistently, and call bdev_direct_access() for the dax capability
> check.
...
> +bool bdev_dax_capable(struct block_device *bdev)
> +{
> +	struct gendisk *disk = bdev->bd_disk;
> +	struct blk_dax_ctl dax = {
> +		.size = PAGE_SIZE,
> +	};
> +
> +	if (!IS_ENABLED(CONFIG_FS_DAX))
> +		return false;

Frankly, I prefer the #ifdef CONFIG_FS_DAX and just compile the code out
when DAX is not enabled (like it was with blkdev_dax_capable()). That way we
don't grow the kernel for people who don't care about DAX.

								Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR