From mboxrd@z Thu Jan 1 00:00:00 1970 From: Souptick Joarder 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+glpar-linux-rockchip=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, mhocko-IBi9RG/b67k@public.gmane.org, kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, vbabka-AlSwsSmVLrQ@public.gmane.org, riel-ebMLmSuQjDVBDgjK7y7TUQ@public.gmane.org, sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org, rppt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, robin.murphy-5wv7dgnIgG8@public.gmane.org, iamjoonsoo.kim-Hm3cg6mZ9cc@public.gmane.org, treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, stefanr-MtYdepGKPcBMYopoZt5u/LNAH6kLmebB@public.gmane.org, hjc-TNX95d0MmH7DzftRWevZcw@public.gmane.org, heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org, airlied-cv59FeDIM0c@public.gmane.org, oleksandr_andrushchenko-uRwfk40T5oI@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, pawel-FA/gS7QP4orQT0dZR+AlfA@public.gmane.org, kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, mchehab-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, boris.ostrovsky-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, jgross-IBi9RG/b67k@public.gmane.org Cc: linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux1394-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rockchip.vger.kernel.org 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 --- 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