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

Jan Kara
2016-05-11T08:05:57Z

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@suse.com>
SUSE Labs, CR