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

This removes the 'write' and 'force' from get_user_pages() 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>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 8 insertions, 24 deletions

diff --git a/mm/gup.c b/mm/gup.c
index 3cfb55ef0cf4..bbc2e76cdd77 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -987,18 +987,12 @@ EXPORT_SYMBOL(get_user_pages_remote);
  * obviously don't pass FOLL_REMOTE in here.
  */
 long get_user_pages(unsigned long start, unsigned long nr_pages,
-                int write, int force, struct page **pages,
+                unsigned int gup_flags, struct page **pages,
                 struct vm_area_struct **vmas)
 {
-        unsigned int flags = FOLL_TOUCH;
-
-        if (write)
-                flags |= FOLL_WRITE;
-        if (force)
-                flags |= FOLL_FORCE;
-
         return __get_user_pages_locked(current, current->mm, start, nr_pages,
-                                       pages, vmas, NULL, false, flags);
+                                       pages, vmas, NULL, false,
+                                       gup_flags | FOLL_TOUCH);
 }
 EXPORT_SYMBOL(get_user_pages);
 
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index ad1c96ac313c..0b859af06b87 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -850,7 +850,7 @@ static int lookup_node(unsigned long addr)
         struct page *p;
         int err;
 
-        err = get_user_pages(addr & PAGE_MASK, 1, 0, 0, &p, NULL);
+        err = get_user_pages(addr & PAGE_MASK, 1, 0, &p, NULL);
         if (err >= 0) {
                 err = page_to_nid(p);
                 put_page(p);
diff --git a/mm/nommu.c b/mm/nommu.c
index 842cfdd1a31e..70cb844dfd95 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -160,18 +160,11 @@ finish_or_fault:
  * - don't permit access to VMAs that don't support it, such as I/O mappings
  */
 long get_user_pages(unsigned long start, unsigned long nr_pages,
-                    int write, int force, struct page **pages,
+                    unsigned int gup_flags, struct page **pages,
                     struct vm_area_struct **vmas)
 {
-        int flags = 0;
-
-        if (write)
-                flags |= FOLL_WRITE;
-        if (force)
-                flags |= FOLL_FORCE;
-
-        return __get_user_pages(current, current->mm, start, nr_pages, flags,
-                                pages, vmas, NULL);
+        return __get_user_pages(current, current->mm, start, nr_pages,
+                                gup_flags, pages, vmas, NULL);
 }
 EXPORT_SYMBOL(get_user_pages);
 
@@ -179,10 +172,7 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
                             unsigned int gup_flags, struct page **pages,
                             int *locked)
 {
-        int write = gup_flags & FOLL_WRITE;
-        int force = gup_flags & FOLL_FORCE;
-
-        return get_user_pages(start, nr_pages, write, force, pages, NULL);
+        return get_user_pages(start, nr_pages, gup_flags, pages, NULL);
 }
 EXPORT_SYMBOL(get_user_pages_locked);