Re: [linux-next:master 5141/5361] include/linux/hmm.h:102:22: error: field 'mmu_notifier' has incomplete type

[Jerome Glisse <jglisse@redhat.com>]

----- Original Message -----
> On Sat, Feb 02, 2019 at 12:14:13AM +0800, kbuild test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > master
> > head:   9fe36dd579c794ae5f1c236293c55fb6847e9654
> > commit: a3402cb621c1b3908600d3f364e991a6c5a8c06e [5141/5361] mm/hmm:
> > improve driver API to work and wait over a range
> > config: x86_64-randconfig-b0-02012138 (attached as .config)
> > compiler: gcc-8 (Debian 8.2.0-14) 8.2.0
> > reproduce:
> >         git checkout a3402cb621c1b3908600d3f364e991a6c5a8c06e
> >         # save the attached .config to linux build tree
> >         make ARCH=x86_64
> > 
> > All errors (new ones prefixed by >>):
> > 
> >    In file included from kernel/memremap.c:14:
> > >> include/linux/hmm.h:102:22: error: field 'mmu_notifier' has incomplete
> > >> type
> >      struct mmu_notifier mmu_notifier;
> >                          ^~~~~~~~~~~~
> > 
> > vim +/mmu_notifier +102 include/linux/hmm.h
> > 
> >     81
> >     82
> >     83	/*
> >     84	 * struct hmm - HMM per mm struct
> >     85	 *
> >     86	 * @mm: mm struct this HMM struct is bound to
> >     87	 * @lock: lock protecting ranges list
> >     88	 * @ranges: list of range being snapshotted
> >     89	 * @mirrors: list of mirrors for this mm
> >     90	 * @mmu_notifier: mmu notifier to track updates to CPU page table
> >     91	 * @mirrors_sem: read/write semaphore protecting the mirrors list
> >     92	 * @wq: wait queue for user waiting on a range invalidation
> >     93	 * @notifiers: count of active mmu notifiers
> >     94	 * @dead: is the mm dead ?
> >     95	 */
> >     96	struct hmm {
> >     97		struct mm_struct	*mm;
> >     98		struct kref		kref;
> >     99		struct mutex		lock;
> >    100		struct list_head	ranges;
> >    101		struct list_head	mirrors;
> >  > 102		struct mmu_notifier	mmu_notifier;
> 
> Only HMM_MIRROR depends on MMU_NOTIFIER, but mmu_notifier in
> the hmm struct is not conditionally dependent HMM_MIRROR.
> The shared config has HMM_MIRROR disabled
> 
> Balbir
> 
> 

I am bad with kconfig simplest fix from my pov is adding
select MMU_NOTIFIER to HMM config as anyway anything that
will have HMM will need notifier.

config HMM
  bool
+ select MMU_NOTIFIER
  select MIGRATE_VMA_HELPER


Cheers,
Jérôme