Re: nfs: add dummy definition for nfsd_file

Mike Snitzer
2025-03-27T02:00:03Z

On Wed, Mar 26, 2025 at 09:59:19PM +0100, Pali Rohár wrote:
> On Wednesday 26 March 2025 08:33:32 Jeff Johnson wrote:
> > On 3/26/2025 8:09 AM, Mike Snitzer wrote:
> > > Add dummy definition for nfsd_file in both nfslocalio.c and localio.c
> > > so older gcc (e.g. EL8's 8.5.0) can be used. Older gcc causes RCU
> > > code (rcu_dereference and rcu_access_pointer) to dereference what
> > > should just be an opaque pointer with its use of typeof.
> > >
> > > So without the dummy definition compiling with older gcc fails.
> > >
> > > Link: https://lore.kernel.org/all/Zsyhco1OrOI_uSbd@kernel.org/
> > > Fixes: 55a9742d02eff ("nfs: cache all open LOCALIO nfsd_file(s) in client")
>
> As this change is fixing compile error, should not be there also cc: stable line?

Any commit with a Fixes: tag will automatically be picked up by
stable@ once it is merged. An explicit cc: sttable@ would be
redundant.

> >
> > I saw this issue using crosstools/gcc-13.3.0-nolibc and this patch fixes it.
>
> So maybe the commit message can be adjusted, so it does not say only
> "older gcc"?

I don't see the need to list all compilers, I documented the compiler
that motivated my fix. Fact that it applicable for
crosstools/gcc-13.3.0-nolibc (which I don't have context for what it
is.. but if this commit is needed for it then it is a suspect "new"
compiler).

> > Tested-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
>
> I have tested this change and it fixed compilation for me too. So:
>
> Tested-by: Pali Rohár <pali@kernel.org>
>
> >
> > > Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
> >
> > note this doesn't match the From: address

AFAIK there is no requirement that an S-o-B tag must match the email
header's From.

Mike