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/misc.c b/fs/cifs/misc.c
index 88786ba..ec36410 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -347,13 +347,13 @@
 		/*  BB Add support for establishing new tCon and SMB Session  */
 		/*      with userid/password pairs found on the smb session   */
 		/*	for other target tcp/ip addresses 		BB    */
-				if (current->fsuid != treeCon->ses->linux_uid) {
+				if (current_fsuid() != treeCon->ses->linux_uid) {
 					cFYI(1, ("Multiuser mode and UID "
 						 "did not match tcon uid"));
 					read_lock(&GlobalSMBSeslock);
 					list_for_each(temp_item, &GlobalSMBSessionList) {
 						ses = list_entry(temp_item, struct cifsSesInfo, cifsSessionList);
-						if (ses->linux_uid == current->fsuid) {
+						if (ses->linux_uid == current_fsuid()) {
 							if (ses->server == treeCon->ses->server) {
 								cFYI(1, ("found matching uid substitute right smb_uid"));
 								buffer->Uid = ses->Suid;