lkml.org 
[lkml]   [2022]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v5 2/7] dax: introduce dax device flag DAXDEV_RECOVERY
On Thu, Feb 3, 2022 at 9:17 PM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Thu, Feb 3, 2022 at 5:43 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > On Wed, Feb 02, 2022 at 09:27:42PM +0000, Jane Chu wrote:
> > > Yeah, I see. Would you suggest a way to pass the indication from
> > > dax_iomap_iter to dax_direct_access that the caller intends the
> > > callee to ignore poison in the range because the caller intends
> > > to do recovery_write? We tried adding a flag to dax_direct_access, and
> > > that wasn't liked if I recall.
> >
> > To me a flag seems cleaner than this magic, but let's wait for Dan to
> > chime in.
>
> So back in November I suggested modifying the kaddr, mainly to avoid
> touching all the dax_direct_access() call sites [1]. However, now
> seeing the code and Chrisoph's comment I think this either wants type
> safety (e.g. 'dax_addr_t *'), or just add a new flag. Given both of
> those options involve touching all dax_direct_access() call sites and
> a @flags operation is more extensible if any other scenarios arrive
> lets go ahead and plumb a flag and skip the magic.

Just to be clear we are talking about a flow like:

flags = 0;
rc = dax_direct_access(..., &kaddr, flags, ...);
if (unlikely(rc)) {
flags |= DAX_RECOVERY;
dax_direct_access(..., &kaddr, flags, ...);
return dax_recovery_{read,write}(..., kaddr, ...);
}
return copy_{mc_to_iter,from_iter_flushcache}(...);

\
 
 \ /
  Last update: 2022-02-04 06:32    [W:0.062 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site