From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Rapoport <rppt-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
Subject: Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and
	vm_insert_range_buggy API
Date: Thu, 7 Feb 2019 17:57:00 +0200
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To: Souptick Joarder <jrdr.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>, Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux-MM <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>, linux1394-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Stephen Rothwell <sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>, oleksandr_andrushchenko-uRwfk40T5oI@public.gmane.org, Russell King - ARM Linux <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>, Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, airlied-cv59FeDIM0c@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, pawel-FA/gS7QP4orQT0dZR+AlfA@public.gmane.org, Rik van Riel <riel-ebMLmSuQjDVBDgjK7y7TUQ@public.gmane.org>, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, rppt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, Boris Ostrovsky <boris.ostrovsky-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>, mchehab-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, iamjoonsoo.kim-Hm3cg6mZ9cc@public.gmane.org, vbabka-AlSwsSmVLrQ@public.gmane.org, Juergen Gross <jgross-IBi9RG/b67k@public.gmane.org>, hjc-TNX95d0MmH7DzftRWevZcw@public.gmane.org, xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org, Kyungmin
List-Id: linux-rockchip.vger.kernel.org

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.

> +/**
> + * __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.