Re: [GIT PULL] workqueue changes for v4.2-rc1

From: Paul E. McKenney
Date: Sat Jun 27 2015 - 12:17:17 EST


On Sat, Jun 27, 2015 at 02:35:56PM +1000, Stephen Rothwell wrote:
> Hi Linus,
>
> On Fri, 26 Jun 2015 20:18:10 -0700 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Fri, Jun 26, 2015 at 9:01 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> > >
> > > Ooh, it isn't in mainline yet but pulling rcu tree will cause a silent
> > > conflict with this pull request which leads to build failure.
> >
> > I tend to try to do a full "make allmodconfig" build between all pull
> > requests (although I can optimize that a bit for very targeted pull
> > requests), so hopefully I'll notice and remember your note.
> >
> > But just in case:
> >
> > > The two colliding commits are.
> > >
> > > 5b95e1af8d17 ("workqueue: wq_pool_mutex protects the attrs-installation")
> > > eeacf8982637 ("rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()")
> > >
> > > The former adds rcu_lockdep_assert() usage and the latter renames and
> > > flips it. It can be resolved by renaming and negating the conditions
> > > in the new usage.
> >
> > it would be great if when I get the RCU pull request that introduces
> > that renaming, whoever sends it to me could remind me about it.
>
> I was wondering why I didn't see that in linux-next ... turns out I
> did, but that rcu commit vanished after June 23 ... I have no idea
> where it went, but it has not been in the last 3 -next releases.

On that date, I moved my rcu/next branch to the commit that I sent to
Ingo in my pull request for the current merge window. As I understand
it, during the merge window, I am not supposed to advertise commits
to -next that are not destined for that merge window. When the merge
window closes, I will rebase the rest of the RCU commits to v4.2-rc1,
at which point an updated version of that commit will reappear.

> If it turns up again, this is the merge fix patch I was using:

Thank you, I will include this.

Thanx, Paul

> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Sat, 20 Jun 2015 19:39:43 +1000
> Subject: [PATCH] workqueue: fix up for rcu_lockdep_assert() rename
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> ---
> kernel/workqueue.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 837427cc5bdf..44cd4144ebcb 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -348,10 +348,10 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
> "sched RCU or wq->mutex should be held")
>
> #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \
> - rcu_lockdep_assert(rcu_read_lock_sched_held() || \
> - lockdep_is_held(&wq->mutex) || \
> - lockdep_is_held(&wq_pool_mutex), \
> - "sched RCU, wq->mutex or wq_pool_mutex should be held")
> + RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \
> + !lockdep_is_held(&wq->mutex) && \
> + !lockdep_is_held(&wq_pool_mutex), \
> + "sched RCU, wq->mutex or wq_pool_mutex should be held")
>
> #define for_each_cpu_worker_pool(pool, cpu) \
> for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
> --
> 2.1.4
>
> --
> Cheers,
> Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>

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