CRED: Wrap task credential accesses in the SMBFS filesystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 3528f40..fc27fbf 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -586,7 +586,7 @@
 		if (parse_options(mnt, raw_data))
 			goto out_bad_option;
 	}
-	mnt->mounted_uid = current->uid;
+	mnt->mounted_uid = current_uid();
 	smb_setcodepage(server, &mnt->codepage);
 
 	/*