From: Souptick Joarder <jrdr.linux@gmail.com> 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 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 Subject: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API Date: Thu, 31 Jan 2019 08:38:12 +0530 Message-ID: <20190131030812.GA2174@jordon-HP-15-Notebook-PC> (raw) 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 <jrdr.linux@gmail.com> Suggested-by: Russell King <linux@armlinux.org.uk> Suggested-by: Matthew Wilcox <willy@infradead.org> --- 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 -- 1.9.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply index Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-31 3:08 Souptick Joarder [this message] 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 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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