Re: [GIT PULL de-alpha] Make core code not need to know about Alpha for v4.15

From: Paul E. McKenney
Date: Wed Oct 25 2017 - 09:18:35 EST


On Wed, Oct 25, 2017 at 11:04:43AM +0200, Ingo Molnar wrote:
>
> * Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On Wed, Oct 25, 2017 at 10:45:48AM +0200, Ingo Molnar wrote:
> > >
> > > * Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > > Hello, Ingo,
> > > >
> > > > This series is a first step towards making the core kernel no longer
> > > > need to consider DEC Alpha as a special case. This is accomplished
> > > > by two sets of patches, followed by a Coccinelle script:
> > > >
> > > > 1. Patches 1/19 through 15/19 in the following patches, which
> > > > change non-Coccinelle-susceptible instances of ACCESS_ONCE()
> > > > to either READ_ONCE() or WRITE_ONCE(), as appropriate. Most of
> > > > these patches are courtesy of Mark Rutland.
> > > >
> > > > 2. Patches 16/19 through 18/19 in the following patches, which
> > > > add smp_read_barrier_depends() to READ_ONCE() and to Alpha's
> > > > value-returning _release and _relaxed atomic read-modify-write
> > > > operations, while also removing lockless_dereference() in favor
> > > > of the modified READ_ONCE().
> > > >
> > > > 3. A patch generated by Coccinelle (script in commit log) that
> > > > converts ACCESS_ONCE() to either READ_ONCE() or WRITE_ONCE(),
> > > > as appropriate. Of course, this patch should not be applied
> > > > as-is to mainline, instead, the Coccinelle script should be
> > > > re-run in order to account for any changes between now and
> > > > the time of merging into mainline.
> > > >
> > > > A later series (most likely targeted to v4.16) will remove instances of
> > > > smp_read_barrier_depends() that are made redundant by this series, that
> > > > is to say, almost all of them.
> > > >
> > > > These changes are available in the git repository at:
> > > >
> > > > git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/alpha-cocci
> > > >
> > > > for you to fetch changes up to d19fa5187a69bd7685e9c7452ce9e339b1b079fc:
> > > >
> > > > COCCINELLE: treewide: kill off ACCESS_ONCE() (2017-10-21 12:52:09 -0700)
> > > >
> > > > ----------------------------------------------------------------
> > > > Mark Rutland (14):
> > > > dm integrity: Kill off ACCESS_ONCE()
> > > > EDAC, altera: Kill off ACCESS_ONCE()
> > > > firmware/ivc: Kill off ACCESS_ONCE()
> > > > fs: dcache: Kill off ACCESS_ONCE()
> > > > fs: ncpfs: Kill off ACCESS_ONCE()
> > > > media: dvb_ringbuffer: Kill off ACCESS_ONCE()
> > > > net: netlink/netfilter: Kill off ACCESS_ONCE()
> > > > net/ipv4/tcp_input.c: Kill off ACCESS_ONCE()
> > > > net: average: Kill off ACCESS_ONCE()
> > > > samples: mic/mpssd/mpssd.c: Kill off ACCESS_ONCE()
> > > > selftests/powerpc: Kill off ACCESS_ONCE()
> > > > workqueue: Kill off ACCESS_ONCE()
> > > > rcutorture: formal: Prepare for ACCESS_ONCE() removal
> > > > COCCINELLE: treewide: kill off ACCESS_ONCE()
> > >
> > > None of the patches from Mark include your Signed-off-by - I'll add them, let me
> > > know if that's not OK. I suppose this happened because you rebased his tree?
> >
> > I did pull his tree rather than applying from email, [...]
>
> You might have pulled it, but the commits in rcu/alpha-cocci suggest that the tree
> was also rebased:
>
> commit d19fa5187a69bd7685e9c7452ce9e339b1b079fc
> Author: Mark Rutland <mark.rutland@xxxxxxx>
> AuthorDate: Thu Oct 19 10:42:03 2017 -0700
> Commit: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> CommitDate: Sat Oct 21 12:52:09 2017 -0700
>
> COCCINELLE: treewide: kill off ACCESS_ONCE()
>
> Note the "Commit:" field which says the commit was created by you, not by Mark.

Hmmm... Looking back through my old versions, it looks like my original
pull from Mark's git tree did the rebase. Not sure how that happened,
given that both are based on v4.14-rc4. I am going to have to proceed
more carefully next time!

Thanx, Paul