CRED: Use creds in file structs

Attach creds to file structs and discard f_uid/f_gid.

file_operations::open() methods (such as hppfs_open()) should use file->f_cred
rather than current_cred().  At the moment file->f_cred will be current_cred()
at this point.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 0ebaff6..0ef4e30 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -260,14 +260,14 @@
 static u32 flow_get_skuid(const struct sk_buff *skb)
 {
 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
-		return skb->sk->sk_socket->file->f_uid;
+		return skb->sk->sk_socket->file->f_cred->fsuid;
 	return 0;
 }
 
 static u32 flow_get_skgid(const struct sk_buff *skb)
 {
 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
-		return skb->sk->sk_socket->file->f_gid;
+		return skb->sk->sk_socket->file->f_cred->fsgid;
 	return 0;
 }