Re: [PATCH 2/5] mm: gup: add __get_user_pages_unlocked to customize gup_flags

[Kirill A. Shutemov]

On Wed, Oct 29, 2014 at 05:35:17PM +0100, Andrea Arcangeli wrote:
> Some caller (like KVM) may want to set the gup_flags like
> FOLL_HWPOSION to get a proper -EHWPOSION retval instead of -EFAULT to
> take a more appropriate action if get_user_pages runs into a memory
> failure.
> 
> Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> ---
>  include/linux/mm.h |  4 ++++
>  mm/gup.c           | 44 ++++++++++++++++++++++++++++++++------------
>  mm/nommu.c         | 16 +++++++++++++---
>  3 files changed, 49 insertions(+), 15 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 99831d9..9a5ada3 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1222,6 +1222,10 @@ long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm,
>  		    unsigned long start, unsigned long nr_pages,
>  		    int write, int force, struct page **pages,
>  		    int *locked);
> +long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
> +			       unsigned long start, unsigned long nr_pages,
> +			       int write, int force, struct page **pages,
> +			       unsigned int gup_flags);
>  long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
>  		    unsigned long start, unsigned long nr_pages,
>  		    int write, int force, struct page **pages);
> diff --git a/mm/gup.c b/mm/gup.c
> index a8521f1..01534ff 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -591,9 +591,9 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
>  						int write, int force,
>  						struct page **pages,
>  						struct vm_area_struct **vmas,
> -						int *locked, bool notify_drop)
> +						int *locked, bool notify_drop,
> +						unsigned int flags)

Argument list getting too long. Should we consider packing them into a
struct?

-- 
 Kirill A. Shutemov
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