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From:   Souptick Joarder <jrdr.linux@gmail.com>
Date:   Thu, 7 Feb 2019 21:37:08 +0530
Message-ID: <CAFqt6zbE0JD09ibp3jZ0rr5xp52SEK+Pi6pGMQwSp_=d0edy7g@mail.gmail.com>
Subject: Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and
 vm_insert_range_buggy API
To:     Mike Rapoport <rppt@linux.ibm.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@suse.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        vbabka@suse.cz, Rik van Riel <riel@surriel.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        rppt@linux.vnet.ibm.com, Peter Zijlstra <peterz@infradead.org>,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        robin.murphy@arm.com, iamjoonsoo.kim@lge.com, treding@nvidia.com,
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On Thu, Feb 7, 2019 at 9:27 PM Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> Hi Souptick,
>
> On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote:
> > Hi Mike,
> >
> > Just thought to take opinion for documentation before placing it in v3.
> > Does it looks fine ?
>
> Overall looks good to me. Several minor points below.

Thanks Mike. Noted.
Shall I consider it as *Reviewed-by:* with below changes ?

>
> > +/**
> > + * __vm_insert_range - insert range of kernel pages into user vma
> > + * @vma: user vma to map to
> > + * @pages: pointer to array of source kernel pages
> > + * @num: number of pages in page array
> > + * @offset: user's requested vm_pgoff
> > + *
> > + * This allow drivers to insert range of kernel pages into a user vma.
>
>           allows
> > + *
> > + * Return: 0 on success and error code otherwise.
> > + */
> > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages,
> > +                               unsigned long num, unsigned long offset)
> >
> >
> > +/**
> > + * vm_insert_range - insert range of kernel pages starts with non zero offset
> > + * @vma: user vma to map to
> > + * @pages: pointer to array of source kernel pages
> > + * @num: number of pages in page array
> > + *
> > + * Maps an object consisting of `num' `pages', catering for the user's
>                                    @num pages
> > + * requested vm_pgoff
> > + *
> > + * If we fail to insert any page into the vma, the function will return
> > + * immediately leaving any previously inserted pages present.  Callers
> > + * from the mmap handler may immediately return the error as their caller
> > + * will destroy the vma, removing any successfully inserted pages. Other
> > + * callers should make their own arrangements for calling unmap_region().
> > + *
> > + * Context: Process context. Called by mmap handlers.
> > + * Return: 0 on success and error code otherwise.
> > + */
> > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages,
> > +                               unsigned long num)
> >
> >
> > +/**
> > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset
> > + * @vma: user vma to map to
> > + * @pages: pointer to array of source kernel pages
> > + * @num: number of pages in page array
> > + *
> > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to
>
>                                                                   the offset
>
> > + * 0. This function is intended for the drivers that did not consider
> > + * @vm_pgoff.
> > + *
> > + * Context: Process context. Called by mmap handlers.
> > + * Return: 0 on success and error code otherwise.
> > + */
> > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages,
> > +                               unsigned long num)
> >
>
> --
> Sincerely yours,
> Mike.
>