diff options
| -rw-r--r-- | include/linux/mm.h | 4 | ||||
| -rw-r--r-- | mm/memory.c | 81 | ||||
| -rw-r--r-- | mm/nommu.c | 14 |
3 files changed, 99 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index abb7eb7ef0f2..912614fbbef3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2579,6 +2579,10 @@ struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr); 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_map_pages(struct vm_area_struct *vma, struct page **pages, + unsigned long num); +int vm_map_pages_zero(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 9b68a72f8c17..96f1d473c89a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1527,6 +1527,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, } EXPORT_SYMBOL(vm_insert_page); +/* + * __vm_map_pages - maps 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 map range of kernel pages into a user vma. + * + * Return: 0 on success and error code otherwise. + */ +static int __vm_map_pages(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_map_pages - maps 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 + * + * 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_map_pages(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return __vm_map_pages(vma, pages, num, vma->vm_pgoff); +} +EXPORT_SYMBOL(vm_map_pages); + +/** + * vm_map_pages_zero - map 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_map_pages(), except that it explicitly sets the offset + * to 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_map_pages_zero(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return __vm_map_pages(vma, pages, num, 0); +} +EXPORT_SYMBOL(vm_map_pages_zero); + 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 749276beb109..b492fd1fcf9f 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_map_pages(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_map_pages); + +int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_map_pages_zero); + /* * sys_brk() for the most part doesn't need the global kernel * lock, except when an application is doing something nasty |