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Date:   Tue, 22 Jan 2019 11:57:48 +0100
From:   Christian Brauner <christian@brauner.io>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>
Subject: Re: linux-next: manual merge of the pidfd tree with the y2038 tree
Message-ID: <20190122105747.6gxvghn7n5dxa65w@brauner.io>
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On Tue, Jan 22, 2019 at 11:48:12AM +0100, Arnd Bergmann wrote:
> On Tue, Jan 22, 2019 at 11:30 AM Christian Brauner <christian@brauner.io> wrote:
> >
> > On Tue, Jan 22, 2019 at 10:31:46AM +0100, Christian Brauner wrote:
> > > On Tue, Jan 22, 2019 at 10:26:56AM +0100, Arnd Bergmann wrote:
> > > > On Mon, Jan 21, 2019 at 11:48 PM Christian Brauner <christian@brauner.io> wrote:
> > > > >
> > > > > On Mon, Jan 21, 2019 at 03:44:17PM -0700, Jens Axboe wrote:
> > > > > > On 1/21/19 1:23 PM, Christian Brauner wrote:
> > > > > > > On Mon, Jan 21, 2019 at 09:15:27PM +0100, Arnd Bergmann wrote:
> > > > > > >> On Mon, Jan 21, 2019 at 8:13 PM Christian Brauner <christian@brauner.io> wrote:
> > > > > > >>> On Mon, Jan 21, 2019 at 06:16:22PM +0100, Arnd Bergmann wrote:
> > > > > > >>>> On Mon, Jan 21, 2019 at 4:40 AM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> > > > > > >>>
> > > > > > >>> I plan on sending the pidfd branch with the new pidfd_send_signal()
> > > > > > >>> syscall for the 5.1 window. Should we somehow coordinate so that our
> > > > > > >>> branches don't conflict? Any suggestions?
> > > > > > >>
> > > > > > >> A conflict can't be avoided, but if you pick system call number 427
> > > > > > >> for pidfd_send_signal, and Jens picks numbers 424 through 426 for
> > > > > > >
> > > > > > > That sounds good to me. Since it's only one syscall for the pidfd branch
> > > > > > > is there anything that speaks against me using 424? Given that the other
> > > > > > > patchset has 4 new syscalls. :)
> > > > > > > Jens, any objections?
> > > > > >
> > > > > > I'm fine with either one, I'll have to renumber in any case. But it's 3
> > > > > > new syscalls (424, 425, 426), not 4.
> > > > > >
> > > > > > Arnd, what's the best way to make this switch now, in my tree? Would be
> > > > >
> > > > > Yeah, I'd like to know that as well.
> > > > >
> > > > > > great if I didn't have to change it again once I make the change.
> > > >
> > > > I'd suggest that you each just take the numbers we talked about and
> > > > add them in your respective git trees, at the end of the current tables.
> >
> > What should we do about unistd.h? We can't just bump that to 42*, right?
> 
> Do you mean the asm-generic uapi header? In my current series, I do that:

Yes. My idea was to only change pidfd_send_signal's entry to 424 and
leave the other ones untouched:

 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index b77538af7aca..4d86d0787d99 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -740,7 +740,7 @@ __SC_COMP(__NR_io_pgetevents, sys_io_pgetevents, compat_sys_io_pgetevents)
 __SYSCALL(__NR_rseq, sys_rseq)
 #define __NR_kexec_file_load 294
 __SYSCALL(__NR_kexec_file_load,     sys_kexec_file_load)
-#define __NR_pidfd_send_signal 295
+#define __NR_pidfd_send_signal 424
 __SYSCALL(__NR_pidfd_send_signal, sys_pidfd_send_signal)

and also leave

#undef __NR_syscalls
#define __NR_syscalls 296

Does that work to avoid the merge conflict or do you need something
more?

Christian