Re: [mmotm:master 229/385] fs/hugetlbfs/inode.c:578:13: error: 'struct vm_area_struct' has no member named 'vm_policy'

[Michal Hocko <mhocko@suse.com>]

On Fri 24-07-15 10:27:02, Mike Kravetz wrote:
> On 07/23/2015 03:18 PM, kbuild test robot wrote:
> >tree:   git://git.cmpxchg.org/linux-mmotm.git master
> >head:   61f5f835b6f06fbc233481b5d3c0afd71ecf54e8
> >commit: 0c5e1e8ed55974975bb829e4b93cf19aa0dfcafc [229/385] hugetlbfs: add hugetlbfs_fallocate()
> >config: i386-randconfig-r0-201529 (attached as .config)
> >reproduce:
> >   git checkout 0c5e1e8ed55974975bb829e4b93cf19aa0dfcafc
> >   # save the attached .config to linux build tree
> >   make ARCH=i386
> >
> >All error/warnings (new ones prefixed by >>):
> >
> >    fs/hugetlbfs/inode.c: In function 'hugetlbfs_fallocate':
> >>>fs/hugetlbfs/inode.c:578:13: error: 'struct vm_area_struct' has no member named 'vm_policy'
> >       pseudo_vma.vm_policy =
> >                 ^
> >>>fs/hugetlbfs/inode.c:579:4: error: implicit declaration of function 'mpol_shared_policy_lookup' [-Werror=implicit-function-declaration]
> >        mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
> >        ^
> >    fs/hugetlbfs/inode.c:595:28: error: 'struct vm_area_struct' has no member named 'vm_policy'
> >        mpol_cond_put(pseudo_vma.vm_policy);
> >                                ^
> >    fs/hugetlbfs/inode.c:601:27: error: 'struct vm_area_struct' has no member named 'vm_policy'
> >       mpol_cond_put(pseudo_vma.vm_policy);
> >                               ^
> >    cc1: some warnings being treated as errors
> >
> >vim +578 fs/hugetlbfs/inode.c
> >
> >    572			if (signal_pending(current)) {
> >    573				error = -EINTR;
> >    574				break;
> >    575			}
> >    576	
> >    577			/* Get policy based on index */
> >  > 578			pseudo_vma.vm_policy =
> >  > 579				mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
> >    580								index);
> >    581	
> >    582			/* addr is the offset within the file (zero based) */
> >
> >---
> >0-DAY kernel test infrastructure                Open Source Technology Center
> >https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
> >
> 
> Michal already added a patch to mmotm.  The patch below is functionally
> equivalent but moves the #ifdef out of the executable code path, and
> modifies a comment.  This has been functional/stress tested in a kernel
> without CONFIG_NUMA defined.

I will drop my quick hack once Andrew picks your patch which is indeed
better. 

One nit below...

> hugetlbfs: build fix fallocate if not CONFIG_NUMA
> 
> When fallocate preallocation allocates pages, it will use the
> defined numa policy.  However, if numa is not defined there is
> no such policy and no code should reference numa policy.  Create
> wrappers to isolate policy manipulation code that are NOOP in
> the non-NUMA case.
> 
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---
>  fs/hugetlbfs/inode.c | 39 ++++++++++++++++++++++++++++++---------
>  1 file changed, 30 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index d977cae..4bae359 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -85,6 +85,29 @@ static const match_table_t tokens = {
>  	{Opt_err,	NULL},
>  };
> 
> +#ifdef CONFIG_NUMA
> +static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
> +					struct inode *inode, pgoff_t index)
> +{
> +	vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
> +							index);
> +}
> +
> +static inline void hugetlb_vma_mpol_cond_put(struct vm_area_struct *vma)

The naming could be better. What about hugetlb_drop_vma_policy to be
symmetric to hugetlb_set_vma_policy. Or is there any reason to expose
that this is a cond_put?
-- 
Michal Hocko
SUSE Labs

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