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

This removes the 'write' and 'force' from get_user_pages_remote() 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: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 6fcfb3f7b137..4e497b9ee71e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -191,6 +191,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 {
         struct page *page;
         int ret;
+        unsigned int gup_flags = FOLL_FORCE;
 
 #ifdef CONFIG_STACK_GROWSUP
         if (write) {
@@ -199,12 +200,16 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                         return NULL;
         }
 #endif
+
+        if (write)
+                gup_flags |= FOLL_WRITE;
+
         /*
          * We are doing an exec().  'current' is the process
          * doing the exec and bprm->mm is the new process's mm.
          */
-        ret = get_user_pages_remote(current, bprm->mm, pos, 1, write,
-                        1, &page, NULL);
+        ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags,
+                        &page, NULL);
         if (ret <= 0)
                 return NULL;