CRED: Wrap task credential accesses in the CIFS 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: Steve French <sfrench@samba.org>
Cc: linux-cifs-client@lists.samba.org
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index e9f9248..e5dca9a 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -833,8 +833,8 @@
 	/* null target name indicates to use *SMBSERVR default called name
 	   if we end up sending RFC1001 session initialize */
 	vol->target_rfc1001_name[0] = 0;
-	vol->linux_uid = current->uid;	/* current->euid instead? */
-	vol->linux_gid = current->gid;
+	vol->linux_uid = current_uid();  /* use current_euid() instead? */
+	vol->linux_gid = current_gid();
 	vol->dir_mode = S_IRWXUGO;
 	/* 2767 perms indicate mandatory locking support */
 	vol->file_mode = (S_IRWXUGO | S_ISGID) & (~S_IXGRP);