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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oQ4Ilbn2E5O3fse3aFqgWsQmQAFvePOUeZWey4DXpkM=; b=Cv2Jo/uACKD7qmIbgu0hRQxw7mU+Wk/Sf60UiervINlZDoVTERVC+vgYeN2pvi6veD xMHNVONmDJpHEjD7M9892Ogug+mOL+1jsTolkLFaIh0PtCcmsgTqGGam0VuHmmQ3pU1E v+NKrzicMOeAUYkQy7JnReq32Vu5G/1XBaxa2bJP/GIbzuYauXvvBygmYLF2z8XWFMTz wfdZ+pgVJJn/2DdZxTPSnqlmRINPNhcHoIq/AblsVb59/QwXr5jZcMChpC+proD0JOvq wObt5CN87wxyjzOUvcaP+ta0tOsYlA5W0ooLRVFImdDWzfbPYXDwKUX/flP5/VXTyVRb QwLA== X-Gm-Message-State: AHQUAuZqC9kY2jRNr3ZN+hLndjRQk8qBjKx3Jzy+Yq7UDLeSpw2/qo76 /5XVIg0weeZzSR4lai6C4VpBzFvb6w2MC45DgH0= X-Google-Smtp-Source: AHgI3IYz0SkMlWyxEeQhmXaahAF/5quTQnuzAn7bE9wiMnoPq679b6hVT3lDwP3on5fiZwP5X0S2WjPjR8kO/5pnmkU= X-Received: by 2002:ac2:5496:: with SMTP id t22mr1036162lfk.31.1549603349625; Thu, 07 Feb 2019 21:22:29 -0800 (PST) MIME-Version: 1.0 References: <20190131030812.GA2174@jordon-HP-15-Notebook-PC> <20190131083842.GE28876@rapoport-lnx> <20190207164739.GX21860@bombadil.infradead.org> In-Reply-To: <20190207164739.GX21860@bombadil.infradead.org> From: Souptick Joarder Date: Fri, 8 Feb 2019 10:52:16 +0530 Message-ID: Subject: Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API To: Matthew Wilcox X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190207_212231_999473_5CDDD697 X-CRM114-Status: GOOD ( 20.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Hocko , Heiko Stuebner , Peter Zijlstra , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Linux-MM , linux1394-devel@lists.sourceforge.net, Marek Szyprowski , Stephen Rothwell , oleksandr_andrushchenko@epam.com, joro@8bytes.org, Russell King - ARM Linux , iommu@lists.linux-foundation.org, Mike Rapoport , airlied@linux.ie, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, treding@nvidia.com, linux-media@vger.kernel.org, Kees Cook , pawel@osciak.com, Rik van Riel , rppt@linux.vnet.ibm.com, Boris Ostrovsky , mchehab@kernel.org, iamjoonsoo.kim@lge.com, vbabka@suse.cz, Juergen Gross , hjc@rock-chips.com, xen-devel@lists.xen.org, Kyungmin Park , stefanr@s5r6.in-berlin.de, Andrew Morton , robin.murphy@arm.com, "Kirill A. Shutemov" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 7, 2019 at 10:17 PM Matthew Wilcox 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 ) ? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel