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bh=r3ZyznqxsnQ3TNNkU3/a+vc/4Jb+njKidr9y0sWTaqQ=; b=SslurM3H+vL+3L88Uldu489QLK4KzDzyx3J13NxZYrnszvnJFRbE5TCIJUn7NtobXk +VADTzsRCI+DouAZdWwO6WWvEkqEXr6DKIzCWp3TQjfTCabRnbGLccvCJY168ZLU8wxd PWPkDRuhU0p0ooYZddzkjaaGz2ZaXqJ7krtUgaBwAgowEm8rWwTwuN0Pfypbz5S6zWKr sS6PwSUrYeI/7Cr3QIm+JQeHre1dIClGxfhTbe2eZ8T6ialEpB7wSZM8ZTqY4Gh4lZCW hGDnX8YcYZYz+PLBAB9Rcq5NmChAH8Xu2cylhI+R1240bSILSiNtcRKJtPjOKkR1HSg6 CwRg== X-Gm-Message-State: AJcUukdsS5AtG+lpxGhhp3Elf6w3ZI7ZaOTyp8uvpuC+e/+gmxZAgbuz gG5nyrpZytRVCsWjY7WPUOc= X-Google-Smtp-Source: ALg8bN77ulDzMTd0u5w2yF1CIUMFdckIxmL4CuhfCBgk9u/Rrp9Yr7EoBKetWq6gkN0hMfNxE8FzMw== X-Received: by 2002:a17:902:4225:: with SMTP id g34mr33628031pld.152.1548903839516; Wed, 30 Jan 2019 19:03:59 -0800 (PST) Received: from jordon-HP-15-Notebook-PC ([106.51.20.103]) by smtp.gmail.com with ESMTPSA id l184sm5303074pfc.112.2019.01.30.19.03.57 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 30 Jan 2019 19:03:58 -0800 (PST) Date: Thu, 31 Jan 2019 08:38:12 +0530 From: Souptick Joarder To: 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, robin.murphy@arm.com, 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 Subject: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API Message-ID: <20190131030812.GA2174@jordon-HP-15-Notebook-PC> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190130_190400_311520_9722C761 X-CRM114-Status: GOOD ( 16.67 ) 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 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 new functions and use it across the drivers. vm_insert_range() is the API which could be used to mapped kernel memory/pages in drivers which has considered vm_pgoff vm_insert_range_buggy() is the API which could be used to map range of kernel memory/pages in drivers which has not considered vm_pgoff. vm_pgoff is passed default as 0 for those drivers. We _could_ then at a later "fix" these drivers which are using vm_insert_range_buggy() to behave according to the normal vm_pgoff offsetting simply by removing the _buggy suffix on the function name and if that causes regressions, it gives us an easy way to revert. Signed-off-by: Souptick Joarder Suggested-by: Russell King Suggested-by: Matthew Wilcox Tested-by: Heiko Stuebner --- include/linux/mm.h | 4 +++ mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/nommu.c | 14 ++++++++++ 3 files changed, 99 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb640..25752b0 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2565,6 +2565,10 @@ 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, struct page **pages, + unsigned long num); +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num); 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 e11ca9d..0a4bf57 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, } EXPORT_SYMBOL(vm_insert_page); +/** + * __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 allows drivers to insert range of kernel pages they've allocated + * into a 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. + * 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) +{ + unsigned long count = vma_pages(vma); + unsigned long uaddr = vma->vm_start; + int ret, i; + + /* Fail if the user requested offset is beyond the end of the object */ + if (offset > num) + return -ENXIO; + + /* Fail if the user requested size exceeds available object size */ + if (count > num - offset) + return -ENXIO; + + for (i = 0; i < count; i++) { + ret = vm_insert_page(vma, uaddr, pages[offset + i]); + if (ret < 0) + return ret; + uaddr += PAGE_SIZE; + } + + return 0; +} + +/** + * 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 + * requested vm_pgoff + * + * 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) +{ + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); +} +EXPORT_SYMBOL(vm_insert_range); + +/** + * 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 + * + * Maps a set of pages, always starting at page[0] + * + * 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) +{ + return __vm_insert_range(vma, pages, num, 0); +} +EXPORT_SYMBOL(vm_insert_range_buggy); + static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn, pgprot_t prot, bool mkwrite) { diff --git a/mm/nommu.c b/mm/nommu.c index 749276b..21d101e 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -473,6 +473,20 @@ 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, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_insert_range); + +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_insert_range_buggy); + /* * sys_brk() for the most part doesn't need the global kernel * lock, except when an application is doing something nasty