Re: [PATCH v3] bpf.2: Use standard types and attributes

[Daniel Borkmann]

On 5/16/21 11:16 AM, Alejandro Colomar (man-pages) wrote:
> On 5/15/21 9:01 PM, Alejandro Colomar wrote:
> > Some manual pages are already using C99 syntax for integral
> > types 'uint32_t', but some aren't.  There are some using kernel
> > syntax '__u32'.  Fix those.
> >
> > Both the kernel and the standard types are 100% binary compatible,
> > and the source code differences between them are very small, and
> > not important in a manual page:
> >
> > - Some of them are implemented with different underlying types
> >    (e.g., s64 is always long long, while int64_t may be long long
> >    or long, depending on the arch).  This causes the following
> >    differences.
> >
> > - length modifiers required by printf are different, resulting in
> >    a warning ('-Wformat=').
> >
> > - pointer assignment causes a warning:
> >    ('-Wincompatible-pointer-types'), but there aren't any pointers
> >    in this page.
> >
> > But, AFAIK, all of those warnings can be safely ignored, due to
> > the binary compatibility between the types.
> >
> > ...
> >
> > Some pages also document attributes, using GNU syntax
> > '__attribute__((xxx))'.  Update those to use the shorter and more
> > portable C11 keywords such as 'alignas()' when possible, and C2x
> > syntax '[[gnu::xxx]]' elsewhere, which hasn't been standardized
> > yet, but is already implemented in GCC, and available through
> > either --std=c2x or any of the --std=gnu... options.
> >
> > The standard isn't very clear on how to use alignas() or
> > [[]]-style attributes, and the GNU documentation isn't better, so
> > the following link is a useful experiment about the different
> > alignment syntaxes:
> > __attribute__((aligned())), alignas(), and [[gnu::aligned()]]:
> > <https://stackoverflow.com/q/67271825/6872717>
> >
> > Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx>
> Discussion: <https://lore.kernel.org/linux-man/6740a229-842e-b368-86eb-defc786b3658@xxxxxxxxx/T/>
> > Nacked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> > Nacked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

You forgot to retain my ...

Nacked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

> > Acked-by: Zack Weinberg <zackw@xxxxxxxxx>
> > Cc: LKML <linux-kernel@xxxxxxxxxxxxxxx>
> > Cc: glibc <libc-alpha@xxxxxxxxxxxxxx>
> > Cc: GCC <gcc-patches@xxxxxxxxxxx>
> > Cc: bpf <bpf@xxxxxxxxxxxxxxx>
> > Cc: David Laight <David.Laight@xxxxxxxxxx>
> > Cc: Joseph Myers <joseph@xxxxxxxxxxxxxxxx>
> > Cc: Florian Weimer <fweimer@xxxxxxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > ---
> >   man2/bpf.2 | 49 ++++++++++++++++++++++++-------------------------
> >   1 file changed, 24 insertions(+), 25 deletions(-)