commit c164154f66f0c9b02673f07aa4f044f1d9c70274
author Lorenzo Stoakes <lstoakes@gmail.com> Thu Oct 13 01:20:13 2016 +0100
committer Linus Torvalds <torvalds@linux-foundation.org> Tue Oct 18 14:13:37 2016 -0700
tree fdfdc521c7cadcbbd8b4bb6bd85e8b17c13fcb13
parent d4944b0ecec0af882483fe44b66729316e575208

mm: replace get_user_pages_unlocked() write/force parameters with gup_flags

This removes the 'write' and 'force' use from get_user_pages_unlocked()
and replaces them with 'gup_flags' to make the use of FOLL_FORCE
explicit in callers as use of this flag can result in surprising
behaviour (and hence bugs) within the mm subsystem.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/gup.c

diff --git a/mm/gup.c b/mm/gup.c
index e997f54..373d1ec 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -907,17 +907,10 @@
  * "force" parameter).
  */
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
-			     int write, int force, struct page **pages)
+			     struct page **pages, unsigned int gup_flags)
 {
-	unsigned int flags = FOLL_TOUCH;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
 	return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
-					 pages, flags);
+					 pages, gup_flags | FOLL_TOUCH);
 }
 EXPORT_SYMBOL(get_user_pages_unlocked);
 
@@ -1535,7 +1528,8 @@
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
+		ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
+				write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {

mm/nommu.c

diff --git a/mm/nommu.c b/mm/nommu.c
index 925dcc1..7e27add 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -197,17 +197,10 @@
 EXPORT_SYMBOL(__get_user_pages_unlocked);
 
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
-			     int write, int force, struct page **pages)
+			     struct page **pages, unsigned int gup_flags)
 {
-	unsigned int flags = 0;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
 	return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
-					 pages, flags);
+					 pages, gup_flags);
 }
 EXPORT_SYMBOL(get_user_pages_unlocked);
 

mm/util.c

diff --git a/mm/util.c b/mm/util.c
index 662cddf..4c685bd 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -283,7 +283,8 @@
 int __weak get_user_pages_fast(unsigned long start,
 				int nr_pages, int write, struct page **pages)
 {
-	return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
+	return get_user_pages_unlocked(start, nr_pages, pages,
+				       write ? FOLL_WRITE : 0);
 }
 EXPORT_SYMBOL_GPL(get_user_pages_fast);