LSM: shrink the common_audit_data data union

After shrinking the common_audit_data stack usage for private LSM data I'm
not going to shrink the data union.  To do this I'm going to move anything
larger than 2 void * ptrs to it's own structure and require it to be declared
separately on the calling stack.  Thus hot paths which don't need more than
a couple pointer don't have to declare space to hold large unneeded
structures.  I could get this down to one void * by dealing with the key
struct and the struct path.  We'll see if that is helpful after taking care of
networking.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/security/smack/smack.h b/security/smack/smack.h
index ccba382..4ede719 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -325,6 +325,14 @@
 	a->a.smack_audit_data->function = func;
 }
 
+static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
+				   char type, struct lsm_network_audit *net)
+{
+	smk_ad_init(a, func, type);
+	memset(net, 0, sizeof(*net));
+	a->a.u.net = net;
+}
+
 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 					 struct task_struct *t)
 {
@@ -348,7 +356,7 @@
 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 					    struct sock *sk)
 {
-	a->a.u.net.sk = sk;
+	a->a.u.net->sk = sk;
 }
 
 #else /* no AUDIT */