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From: Souptick Joarder <jrdr.linux@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>, Heiko Stuebner <heiko@sntech.de>,
	Peter Zijlstra <peterz@infradead.org>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Linux-MM <linux-mm@kvack.org>,
	linux1394-devel@lists.sourceforge.net,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	oleksandr_andrushchenko@epam.com, joro@8bytes.org,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	iommu@lists.linux-foundation.org,
	Mike Rapoport <rppt@linux.ibm.com>,
	airlied@linux.ie, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, treding@nvidia.com,
	linux-media@vger.kernel.org, Kees Cook <keescook@chromium.org>,
	pawel@osciak.com, Rik van Riel <riel@surriel.com>,
	rppt@linux.vnet.ibm.com,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	mchehab@kernel.org, iamjoonsoo.kim@lge.com, vbabka@suse.cz,
	Juergen Gross <jgross@suse.com>,
	hjc@rock-chips.com, xen-devel@lists.xen.org,
	Kyungmin Park <kyungmin.park@samsung.com>,
	stefanr@s5r6.in-berlin.de,
	Andrew Morton <akpm@linux-foundation.org>,
	robin.murphy@arm.com,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API
Date: Fri, 8 Feb 2019 10:52:16 +0530
Message-ID: <CAFqt6zawBP5Yyy7nfoKz_6ugw8e4MVopvBaeKvaKoXcS-_oSNg@mail.gmail.com> (raw)
In-Reply-To: <20190207164739.GX21860@bombadil.infradead.org>

On Thu, Feb 7, 2019 at 10:17 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote:
> > Just thought to take opinion for documentation before placing it in v3.
> > Does it looks fine ?
> >
> > +/**
> > + * __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.
> > + *
> > + * 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)
>
> For static functions, I prefer to leave off the second '*', ie make it
> formatted like a docbook comment, but not be processed like a docbook
> comment.  That avoids cluttering the html with descriptions of internal
> functions that people can't actually call.
>
> > +/**
> > + * 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
>
> Rather than using `num', you should use @num.
>
> > + * 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
>
> But vm_pgoff isn't a parameter, so it's misleading to format it as such.
>
> > + * 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)
>
> I don't think we should call it 'buggy'.  'zero' would make more sense
> as a suffix.

suffix can be *zero or zero_offset* whichever suits better.

>
> Given how this interface has evolved, I'm no longer sure than
> 'vm_insert_range' makes sense as the name for it.  Is it perhaps
> 'vm_map_object' or 'vm_map_pages'?
>

I prefer vm_map_pages. Considering it, both the interface name can be changed
to *vm_insert_range -> vm_map_pages* and *vm_insert_range_buggy ->
vm_map_pages_{zero/zero_offset}.

As this is only change in interface name and rest of code remain same
shall I post it in v3 ( with additional change log mentioned about interface
name changed) ?

or,

It will be a new patch series ( with carry forward all the Reviewed-by
/ Tested-by on
vm_insert_range/ vm_insert_range_buggy ) ?

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  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-31  3:08 Souptick Joarder
2019-01-31  8:38 ` Mike Rapoport
2019-01-31 10:13   ` Souptick Joarder
2019-01-31 11:06     ` Mike Rapoport
2019-02-07 15:49   ` Souptick Joarder
2019-02-07 15:57     ` Mike Rapoport
2019-02-07 16:07       ` Souptick Joarder
2019-02-07 16:04         ` Mike Rapoport
2019-02-07 16:47     ` Matthew Wilcox
2019-02-08  5:22       ` Souptick Joarder [this message]
2019-02-11 17:06         ` Souptick Joarder
2019-01-31 12:06 ` Heiko Stuebner
2019-01-31 12:31   ` Souptick Joarder
2019-01-31 12:34     ` Heiko Stuebner
2019-02-01 12:38       ` Souptick Joarder

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