Re: [PATCH net-next] tools: Fix MSG_SPLICE_PAGES build error in trace tools

[Paolo Abeni]

On Mon, 2023-06-26 at 14:59 -0700, Namhyung Kim wrote:
> On Mon, Jun 26, 2023 at 2:53 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> > 
> > On Mon, 26 Jun 2023 14:31:39 -0700 Namhyung Kim wrote:
> > > Right, we want to keep the headers files in the tools in sync with
> > > the kernel ones.  And they are used to generate some tables.
> > > Full explanation from Arnaldo below.
> > > 
> > > So I'm ok for the msg_flags.c changes, but please refrain from
> > > changing the header directly.  We will update it later.
> > > 
> > > With that,
> > >   Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > 
> > Ah, missed this email, sounds like this is preferred to Matthieu's
> > fix, we'll take this one.
> 
> Hmm.. I believe they are the same when it comes to the
> changes in the .c file.
> 
> > 
> > > Also I wonder if the tool needs to keep the original flag
> > > (SENDPAGE_NOTLAST) for the older kernels.
> > 
> > That's a bit unclear, because it's just a kernel-internal flag.
> > Future kernels may well use that bit for something else.
> 
> Ah, ok then.  I thought it's a user-visible flag.
> 
> > 
> > Better long term solution would be to use an enum so that the values
> > are included in debuginfo and perf can read them at runtime :(
> 
> Right, we also consider BTF to read the values and hopefully
> get rid of the business of copying kernel headers.

I read all the above as the preferred solution is the one provided by
Mat's patch (not touching socket.h, same changes as here in
msg_flags.c.

As such, I'll restore Mat's patch in PW and will obsolete this one.
Please raise a flag if I'm wrong ;)

Cheers,

Paolo