Subject: Re: linux-next: build failure after merge of the hmm tree

From: Jason Gunthorpe <[email-masked]>
Date: Tue, 9 Jul 2019 12:32:54 +0000

On Tue, Jul 09, 2019 at 10:21:37AM +1000, Stephen Rothwell wrote:
> Hi all,
> 
> On Mon, 1 Jul 2019 21:08:53 +1000 Stephen Rothwell <[email-masked]> wrote:
> >
> > After merging the hmm tree, today's linux-next build (x86_64 allmodconfig)
> > failed like this:
> > 
> > mm/hmm.c: In function 'hmm_get_or_create':
> > mm/hmm.c:50:2: error: implicit declaration of function 'lockdep_assert_held_exclusive'; did you mean 'lockdep_assert_held_once'? [-Werror=implicit-function-declaration]
> >   lockdep_assert_held_exclusive(&mm->mmap_sem);
> >   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   lockdep_assert_held_once
> > 
> > Caused by commit
> > 
> >   8a9320b7ec5d ("mm/hmm: Simplify hmm_get_or_create and make it reliable")
> > 
> > interacting with commit
> > 
> >   9ffbe8ac05db ("locking/lockdep: Rename lockdep_assert_held_exclusive() -> lockdep_assert_held_write()")
> > 
> > from the tip tree.
> > 
> > I have added the following merge fix.
> > 
> > From: Stephen Rothwell <[email-masked]>
> > Date: Mon, 1 Jul 2019 21:05:59 +1000
> > Subject: [PATCH] mm/hmm: fixup for "locking/lockdep: Rename
> >  lockdep_assert_held_exclusive() -> lockdep_assert_held_write()"
> > 
> > Signed-off-by: Stephen Rothwell <[email-masked]>
> >  mm/hmm.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/mm/hmm.c b/mm/hmm.c
> > index c1bdcef403ee..2ddbd589b207 100644
> > +++ b/mm/hmm.c
> > @@ -47,7 +47,7 @@ static struct hmm *hmm_get_or_create(struct mm_struct *mm)
> >  {
> >  	struct hmm *hmm;
> >  
> > -	lockdep_assert_held_exclusive(&mm->mmap_sem);
> > +	lockdep_assert_held_write(&mm->mmap_sem);
> >  
> >  	/* Abuse the page_table_lock to also protect mm->hmm. */
> >  	spin_lock(&mm->page_table_lock);
> > @@ -248,7 +248,7 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
> >   */
> >  int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
> >  {
> > -	lockdep_assert_held_exclusive(&mm->mmap_sem);
> > +	lockdep_assert_held_write(&mm->mmap_sem);
> >  
> >  	/* Sanity check */
> >  	if (!mm || !mirror || !mirror->ops)
> 
> I am still getting this conflict (the commit ids may have changed).
> Just a reminder in case you think Linus may need to know.

Ingo already sent the PR to Linus with the function rename, so I will
take care of it.

Thanks,
Jason