diff options
| -rw-r--r-- | include/linux/mm.h | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index d87a5a5fe87d..f3fd70d6029f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -833,6 +833,39 @@ extern int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags); +#ifdef CONFIG_HAVE_GET_USER_PAGES_FAST +/* + * get_user_pages_fast provides equivalent functionality to get_user_pages, + * operating on current and current->mm (force=0 and doesn't return any vmas). + * + * get_user_pages_fast may take mmap_sem and page tables, so no assumptions + * can be made about locking. get_user_pages_fast is to be implemented in a + * way that is advantageous (vs get_user_pages()) when the user memory area is + * already faulted in and present in ptes. However if the pages have to be + * faulted in, it may turn out to be slightly slower). + */ +int get_user_pages_fast(unsigned long start, int nr_pages, int write, + struct page **pages); + +#else +/* + * Should probably be moved to asm-generic, and architectures can include it if + * they don't implement their own get_user_pages_fast. + */ +#define get_user_pages_fast(start, nr_pages, write, pages) \ +({ \ + struct mm_struct *mm = current->mm; \ + int ret; \ + \ + down_read(&mm->mmap_sem); \ + ret = get_user_pages(current, mm, start, nr_pages, \ + write, 0, pages, NULL); \ + up_read(&mm->mmap_sem); \ + \ + ret; \ +}) +#endif + /* * A callback you can register to apply pressure to ageable caches. * |