NSM: Generate NSMPROC_MON's "priv" argument when nsm_handle is created

Introduce a new data type, used by both the in-kernel NLM and NSM
implementations, that is used to manage the opaque "priv" argument
for the NSMPROC_MON and NLMPROC_SM_NOTIFY calls.

Construct the "priv" cookie when the nsm_handle is created.

The nsm_init_private() function may look a little strange, but it is
roughly equivalent to how the XDR encoder formed the "priv" argument.
It's going to go away soon.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 0792900..c8d18cd 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -201,6 +201,21 @@
 	}
 }
 
+/*
+ * Construct a unique cookie to match this nsm_handle to this monitored
+ * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
+ * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
+ * requests.
+ *
+ * Linux provides the raw IP address of the monitored host,
+ * left in network byte order.
+ */
+static void nsm_init_private(struct nsm_handle *nsm)
+{
+	__be32 *p = (__be32 *)&nsm->sm_priv.data;
+	*p = nsm_addr_in(nsm)->sin_addr.s_addr;
+}
+
 /**
  * nsm_find - Find or create a cached nsm_handle
  * @sap: pointer to socket address of handle to find
@@ -271,6 +286,7 @@
 	nsm->sm_name = (char *) (nsm + 1);
 	memcpy(nsm->sm_name, hostname, hostname_len);
 	nsm->sm_name[hostname_len] = '\0';
+	nsm_init_private(nsm);
 	nsm_display_address((struct sockaddr *)&nsm->sm_addr,
 				nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 	atomic_set(&nsm->sm_count, 1);