mm: clean up get_user_pages_fast() documentation

Move more documentation for get_user_pages_fast into the new kerneldoc comment.
Add some comments for get_user_pages as well.

Also, move get_user_pages_fast declaration up to get_user_pages. It wasn't
there initially because it was once a static inline function.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Andy Grover <andy.grover@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 15 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 33da7f538841..a880161a3854 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -824,8 +824,11 @@ static inline int handle_mm_fault(struct mm_struct *mm,
 extern int make_pages_present(unsigned long addr, unsigned long end);
 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
 
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
-                int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
+int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                        unsigned long start, int len, int write, int force,
+                        struct page **pages, struct vm_area_struct **vmas);
+int get_user_pages_fast(unsigned long start, int nr_pages, int write,
+                        struct page **pages);
 
 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
 extern void do_invalidatepage(struct page *page, unsigned long offset);
@@ -850,19 +853,6 @@ extern int mprotect_fixup(struct vm_area_struct *vma,
                           unsigned long end, unsigned long newflags);
 
 /*
- * 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);
-
-/*
  * A callback you can register to apply pressure to ageable caches.
  *
  * 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'.  It should