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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVI9x-0002jm-4L; Fri, 07 Dec 2018 15:35:21 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVI9q-0001Vo-9z; Fri, 07 Dec 2018 15:35:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6A59A15AB; Fri, 7 Dec 2018 07:35:03 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1847A3F575; Fri, 7 Dec 2018 07:34:57 -0800 (PST) Subject: Re: [PATCH v3 1/9] mm: Introduce new vm_insert_range API To: Souptick Joarder , akpm@linux-foundation.org, willy@infradead.org, mhocko@suse.com, kirill.shutemov@linux.intel.com, vbabka@suse.cz, riel@surriel.com, sfr@canb.auug.org.au, rppt@linux.vnet.ibm.com, peterz@infradead.org, linux@armlinux.org.uk, iamjoonsoo.kim@lge.com, treding@nvidia.com, keescook@chromium.org, m.szyprowski@samsung.com, stefanr@s5r6.in-berlin.de, hjc@rock-chips.com, heiko@sntech.de, airlied@linux.ie, oleksandr_andrushchenko@epam.com, joro@8bytes.org, pawel@osciak.com, kyungmin.park@samsung.com, mchehab@kernel.org, boris.ostrovsky@oracle.com, jgross@suse.com References: <20181206183945.GA20932@jordon-HP-15-Notebook-PC> From: Robin Murphy Message-ID: <53bbc095-c9f5-5d6a-6e50-6e060d17eb68@arm.com> Date: Fri, 7 Dec 2018 15:34:56 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181206183945.GA20932@jordon-HP-15-Notebook-PC> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181207_073514_357140_A90BA63E X-CRM114-Status: GOOD ( 30.24 ) 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: linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, xen-devel@lists.xen.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, linux1394-devel@lists.sourceforge.net, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 06/12/2018 18:39, Souptick Joarder wrote: > Previouly drivers have their own way of mapping range of > kernel pages/memory into user vma and this was done by > invoking vm_insert_page() within a loop. > > As this pattern is common across different drivers, it can > be generalized by creating a new function and use it across > the drivers. > > vm_insert_range is the new API which will be used to map a > range of kernel memory/pages to user vma. > > This API is tested by Heiko for Rockchip drm driver, on rk3188, > rk3288, rk3328 and rk3399 with graphics. > > Signed-off-by: Souptick Joarder > Reviewed-by: Matthew Wilcox > Reviewed-by: Mike Rapoport > Tested-by: Heiko Stuebner > --- > include/linux/mm.h | 2 ++ > mm/memory.c | 38 ++++++++++++++++++++++++++++++++++++++ > mm/nommu.c | 7 +++++++ > 3 files changed, 47 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index fcf9cc9..2bc399f 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2506,6 +2506,8 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, > int remap_pfn_range(struct vm_area_struct *, unsigned long addr, > unsigned long pfn, unsigned long size, pgprot_t); > int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr, > + struct page **pages, unsigned long page_count); > vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, > unsigned long pfn); > vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, > diff --git a/mm/memory.c b/mm/memory.c > index 15c417e..84ea46c 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1478,6 +1478,44 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, > } > > /** > + * vm_insert_range - insert range of kernel pages into user vma > + * @vma: user vma to map to > + * @addr: target user address of this page > + * @pages: pointer to array of source kernel pages > + * @page_count: number of pages need to insert into user vma > + * > + * This allows drivers to insert range of kernel pages they've allocated > + * into a user vma. This is a generic function which drivers can use > + * rather than using their own way of mapping range of kernel pages into > + * user vma. > + * > + * 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, unsigned long addr, > + struct page **pages, unsigned long page_count) > +{ > + unsigned long uaddr = addr; > + int ret = 0, i; Some of the sites being replaced were effectively ensuring that vma and pages were mutually compatible as an initial condition - would it be worth adding something here for robustness, e.g.: + if (page_count != vma_pages(vma)) + return -ENXIO; ? (then you could also clean up a couple more places where you're not already removing such checks) Robin. > + > + for (i = 0; i < page_count; i++) { > + ret = vm_insert_page(vma, uaddr, pages[i]); > + if (ret < 0) > + return ret; > + uaddr += PAGE_SIZE; > + } > + > + return ret; > +} > +EXPORT_SYMBOL(vm_insert_range); > + > +/** > * vm_insert_page - insert single page into user vma > * @vma: user vma to map to > * @addr: target user address of this page > diff --git a/mm/nommu.c b/mm/nommu.c > index 749276b..d6ef5c7 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -473,6 +473,13 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > } > EXPORT_SYMBOL(vm_insert_page); > > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr, > + struct page **pages, unsigned long page_count) > +{ > + return -EINVAL; > +} > +EXPORT_SYMBOL(vm_insert_range); > + > /* > * sys_brk() for the most part doesn't need the global kernel > * lock, except when an application is doing something nasty > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel