selinux: Add a cache for quicker retreival of PKey SIDs

It is likely that the SID for the same PKey will be requested many
times. To reduce the time to modify QPs and process MADs use a cache to
store PKey SIDs.

This code is heavily based on the "netif" and "netport" concept
originally developed by James Morris <jmorris@redhat.com> and Paul Moore
<paul@paul-moore.com> (see security/selinux/netif.c and
security/selinux/netport.c for more information)

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Acked-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/include/ibpkey.h

@@ -0,0 +1,31 @@
+/*
+ * pkey table
+ *
+ * SELinux must keep a mapping of pkeys to labels/SIDs.  This
+ * mapping is maintained as part of the normal policy but a fast cache is
+ * needed to reduce the lookup overhead.
+ *
+ */
+
+/*
+ * (c) Mellanox Technologies, 2016
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _SELINUX_IB_PKEY_H
+#define _SELINUX_IB_PKEY_H
+
+void sel_ib_pkey_flush(void);
+
+int sel_ib_pkey_sid(u64 subnet_prefix, u16 pkey, u32 *sid);
+
+#endif

security/selinux/include/objsec.h

@@ -144,6 +144,12 @@ struct ib_security_struct {
 	u32 sid;        /* SID of the queue pair or MAD agent */
 };
 
+struct pkey_security_struct {
+	u64	subnet_prefix; /* Port subnet prefix */
+	u16	pkey;	/* PKey number */
+	u32	sid;	/* SID of pkey */
+};
+
 extern unsigned int selinux_checkreqprot;
 
 #endif /* _SELINUX_OBJSEC_H_ */