Re: [PATCH] mm: Remove src/dst mm parameter in copy_page_range()

2020-10-02 Thread Peter Xu
On Fri, Oct 02, 2020 at 02:28:58PM -0300, Jason Gunthorpe wrote:
> On Fri, Oct 02, 2020 at 01:14:29PM -0400, Peter Xu wrote:
> > On Fri, Oct 02, 2020 at 08:43:12AM -0300, Jason Gunthorpe wrote:
> > > > -static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct 
> > > > *src_mm,
> > > > -  pmd_t *dst_pmd, pmd_t *src_pmd, struct 
> > > > vm_area_struct *vma,
> > > > -  struct vm_area_struct *new,
> > > > +static int copy_pte_range(pmd_t *dst_pmd, pmd_t *src_pmd,
> > > > +  struct vm_area_struct *vma, struct vm_area_struct 
> > > > *new,
> > > >unsigned long addr, unsigned long end)
> > > 
> > > I link this, my only minor quibble is the mixing of dst/src and new
> > > language, and then reversing the order in each place. Would read
> > > better to be consistent:
> > > 
> > >   copy_pte_range(dst_vma, dst_pmd, src_vma, src_pmd, addr, end)
> > 
> > I have no strong opinion on the ordering, but I agree the names are clearer.
> > Considering normally we put the same type of parameters to be together, how
> > about:
> > 
> >   copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, addr, end)
> 
> I was looking at the order of (dst_pmd, src_pmd, src_vma, dest_vma)
> 
> Whichever, just have some logic to it :)

Oh, sure. :)

-- 
Peter Xu



Re: [PATCH] mm: Remove src/dst mm parameter in copy_page_range()

2020-10-02 Thread Jason Gunthorpe
On Fri, Oct 02, 2020 at 01:14:29PM -0400, Peter Xu wrote:
> On Fri, Oct 02, 2020 at 08:43:12AM -0300, Jason Gunthorpe wrote:
> > > -static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct 
> > > *src_mm,
> > > -pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
> > > -struct vm_area_struct *new,
> > > +static int copy_pte_range(pmd_t *dst_pmd, pmd_t *src_pmd,
> > > +struct vm_area_struct *vma, struct vm_area_struct *new,
> > >  unsigned long addr, unsigned long end)
> > 
> > I link this, my only minor quibble is the mixing of dst/src and new
> > language, and then reversing the order in each place. Would read
> > better to be consistent:
> > 
> >   copy_pte_range(dst_vma, dst_pmd, src_vma, src_pmd, addr, end)
> 
> I have no strong opinion on the ordering, but I agree the names are clearer.
> Considering normally we put the same type of parameters to be together, how
> about:
> 
>   copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, addr, end)

I was looking at the order of (dst_pmd, src_pmd, src_vma, dest_vma)

Whichever, just have some logic to it :)

Jason


Re: [PATCH] mm: Remove src/dst mm parameter in copy_page_range()

2020-10-02 Thread Peter Xu
On Fri, Oct 02, 2020 at 08:43:12AM -0300, Jason Gunthorpe wrote:
> > -static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct 
> > *src_mm,
> > -  pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
> > -  struct vm_area_struct *new,
> > +static int copy_pte_range(pmd_t *dst_pmd, pmd_t *src_pmd,
> > +  struct vm_area_struct *vma, struct vm_area_struct *new,
> >unsigned long addr, unsigned long end)
> 
> I link this, my only minor quibble is the mixing of dst/src and new
> language, and then reversing the order in each place. Would read
> better to be consistent:
> 
>   copy_pte_range(dst_vma, dst_pmd, src_vma, src_pmd, addr, end)

I have no strong opinion on the ordering, but I agree the names are clearer.
Considering normally we put the same type of parameters to be together, how
about:

  copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, addr, end)

Thanks,

-- 
Peter Xu



Re: [PATCH] mm: Remove src/dst mm parameter in copy_page_range()

2020-10-02 Thread Jason Gunthorpe
On Wed, Sep 30, 2020 at 04:49:50PM -0400, Peter Xu wrote:
> Both of the mm pointers are not needed after commit 7a4830c380f3 ("mm/fork:
> Pass new vma pointer into copy_page_range()").
> 
> Reported-by: Kirill A. Shutemov 
> Signed-off-by: Peter Xu 
> ---
>  include/linux/mm.h |  3 +--
>  kernel/fork.c  |  2 +-
>  mm/memory.c| 43 ++-
>  3 files changed, 24 insertions(+), 24 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 16b799a0522c..8a0ec8dce5f6 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1645,8 +1645,7 @@ struct mmu_notifier_range;
>  
>  void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
>   unsigned long end, unsigned long floor, unsigned long ceiling);
> -int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
> - struct vm_area_struct *vma, struct vm_area_struct *new);
> +int copy_page_range(struct vm_area_struct *vma, struct vm_area_struct *new);
>  int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
>  struct mmu_notifier_range *range,
>  pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
> diff --git a/kernel/fork.c b/kernel/fork.c
> index da8d360fb032..5f42d4afe0ae 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -589,7 +589,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
>  
>   mm->map_count++;
>   if (!(tmp->vm_flags & VM_WIPEONFORK))
> - retval = copy_page_range(mm, oldmm, mpnt, tmp);
> + retval = copy_page_range(mpnt, tmp);
>  
>   if (tmp->vm_ops && tmp->vm_ops->open)
>   tmp->vm_ops->open(tmp);
> diff --git a/mm/memory.c b/mm/memory.c
> index fcfc4ca36eba..251bb5082f4e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -957,11 +957,12 @@ page_copy_prealloc(struct mm_struct *src_mm, struct 
> vm_area_struct *vma,
>   return new_page;
>  }
>  
> -static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
> -pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
> -struct vm_area_struct *new,
> +static int copy_pte_range(pmd_t *dst_pmd, pmd_t *src_pmd,
> +struct vm_area_struct *vma, struct vm_area_struct *new,
>  unsigned long addr, unsigned long end)

I link this, my only minor quibble is the mixing of dst/src and new
language, and then reversing the order in each place. Would read
better to be consistent:

  copy_pte_range(dst_vma, dst_pmd, src_vma, src_pmd, addr, end)

Regards,
Jason