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

[Balbir Singh <bsingharora@gmail.com>]

On Fri, Feb 01, 2019 at 06:08:06PM -0500, Jerome Glisse wrote:
> 
> 
> ----- 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
>

Yes

Acked-by: Balbir Singh <bsingharora@gmail.com>
 
> 
> Cheers,
> Jérôme