Re: [PATCH 2/6] dax: prepare dax_direct_access() API with DAXDEV_F_RECOVERY flag

[Christoph Hellwig]

On Wed, Oct 20, 2021 at 06:10:55PM -0600, Jane Chu wrote:
> @@ -156,8 +156,8 @@ bool generic_fsdax_supported(struct dax_device *dax_dev,
>  	}
>  
>  	id = dax_read_lock();
> -	len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
> -	len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
> +	len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn, 0);
> +	len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn, 0);

FYI, I have a series killing this code.  But either way please avoid
these overly long lines.

>  long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
> -		void **kaddr, pfn_t *pfn)
> +		void **kaddr, pfn_t *pfn, unsigned long flags)

API design: I'd usually expect flags before output paramters.