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

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

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@linux-foundation.org> wrote:
> >
> > On Fri, Jun 26, 2015 at 9:01 AM, Tejun Heo <tj@kernel.org> 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@canb.auug.org.au>
> 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@canb.auug.org.au>
> ---
>  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@canb.auug.org.au
>