[PATCH v5 3/4] scm: Convert put_cmsg() to scoped user access

[Christophe Leroy]

Replace the open coded implementation with the scoped user access
guards.

No functional change intended.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
v5: New
---
 net/core/scm.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/net/core/scm.c b/net/core/scm.c
index 66eaee783e8b..cd87f66671aa 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -273,17 +273,13 @@ int put_cmsg(struct msghdr * msg, int level, int type, 
int len, void *data)
 
                check_object_size(data, cmlen - sizeof(*cm), true);
 
-               if (can_do_masked_user_access())
-                       cm = masked_user_access_begin(cm);
-               else if (!user_write_access_begin(cm, cmlen))
-                       goto efault;
-
-               unsafe_put_user(cmlen, &cm->cmsg_len, efault_end);
-               unsafe_put_user(level, &cm->cmsg_level, efault_end);
-               unsafe_put_user(type, &cm->cmsg_type, efault_end);
-               unsafe_copy_to_user(CMSG_USER_DATA(cm), data,
-                                   cmlen - sizeof(*cm), efault_end);
-               user_write_access_end();
+               scoped_user_write_access_size(cm, cmlen, efault) {
+                       unsafe_put_user(cmlen, &cm->cmsg_len, efault);
+                       unsafe_put_user(level, &cm->cmsg_level, efault);
+                       unsafe_put_user(type, &cm->cmsg_type, efault);
+                       unsafe_copy_to_user(CMSG_USER_DATA(cm), data,
+                                           cmlen - sizeof(*cm), efault);
+               }
        } else {
                struct cmsghdr *cm = msg->msg_control;
 
@@ -301,8 +297,6 @@ int put_cmsg(struct msghdr * msg, int level, int type, int 
len, void *data)
        msg->msg_controllen -= cmlen;
        return 0;
 
-efault_end:
-       user_write_access_end();
 efault:
        return -EFAULT;
 }
-- 
2.49.0