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 jrdr.linux@gmail.com Reviewed-by: Matthew Wilcox willy@infradead.org Tested-by: Heiko Stuebner heiko@sntech.de --- include/linux/mm_types.h | 3 +++ mm/memory.c | 38 ++++++++++++++++++++++++++++++++++++++ mm/nommu.c | 7 +++++++ 3 files changed, 48 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5ed8f62..15ae24f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -523,6 +523,9 @@ extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, extern void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end);
+int vm_insert_range(struct vm_area_struct *vma, unsigned long addr, + struct page **pages, unsigned long page_count); + static inline void init_tlb_flush_pending(struct mm_struct *mm) { atomic_set(&mm->tlb_flush_pending, 0); 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; + + 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