Re: [PATCH 3/6] pmem: pmem_dax_direct_access() to honor the DAXDEV_F_RECOVERY flag

Jane Chu
2021-10-21T18:24:27Z

On 10/21/2021 4:23 AM, Christoph Hellwig wrote:
> On Wed, Oct 20, 2021 at 06:10:56PM -0600, Jane Chu wrote:
>> - if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
>> - PFN_PHYS(nr_pages))))
>> + if (unlikely(!(flags & DAXDEV_F_RECOVERY) &&
>> + is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
>> + PFN_PHYS(nr_pages))))
>
> The indentation here is pretty messed up. Something like this would
> be move normal:
>
> if (unlikely(!(flags & DAXDEV_F_RECOVERY) &&
> is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
> PFN_PHYS(nr_pages)))) {
>

Will do.

> but if we don't really need the unlikely we could do an actually
> readable variant:
>
> if (!(flags & DAXDEV_F_RECOVERY) &&
> is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512, PFN_PHYS(nr_pages)))
>

'unlikely' is needed because 'RWF_RECOVERY_DATA' flag is not
recommended for normal preadv2/pwritev2 usage, it's recommended
only if user is aware of or suspect poison in the range.

thanks,
-jane