[PATCH] add process_session() helper routine

Replace occurences of task->signal->session by a new process_session() helper
routine.

It will be useful for pid namespaces to abstract the session pid number.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c
index 1bbefbf..37cad5d 100644
--- a/arch/mips/kernel/irixelf.c
+++ b/arch/mips/kernel/irixelf.c
@@ -1145,7 +1145,7 @@
 	psinfo.pr_pid = prstatus.pr_pid = current->pid;
 	psinfo.pr_ppid = prstatus.pr_ppid = current->parent->pid;
 	psinfo.pr_pgrp = prstatus.pr_pgrp = process_group(current);
-	psinfo.pr_sid = prstatus.pr_sid = current->signal->session;
+	psinfo.pr_sid = prstatus.pr_sid = process_session(current);
 	if (current->pid == current->tgid) {
 		/*
 		 * This is the record for the group leader.  Add in the