lockd: introduce new function to encode private argument in SM_MON requests

Clean up: refactor the encoding of the opaque 16-byte private argument in
xdr_encode_mon().  This will be updated later to support IPv6 addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 25 insertions, 6 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index f2507fec7c6f..e4d563543b11 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -218,6 +218,24 @@ static __be32 *xdr_encode_mon_id(__be32 *p, struct nsm_args *argp)
         return xdr_encode_my_id(p, argp);
 }
 
+/*
+ * The "priv" argument may contain private information required
+ * by the SM_MON call. This information will be supplied in the
+ * SM_NOTIFY call.
+ *
+ * Linux provides the raw IP address of the monitored host,
+ * left in network byte order.
+ */
+static __be32 *xdr_encode_priv(__be32 *p, struct nsm_args *argp)
+{
+        *p++ = argp->addr;
+        *p++ = 0;
+        *p++ = 0;
+        *p++ = 0;
+
+        return p;
+}
+
 static int
 xdr_encode_mon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
 {
@@ -225,11 +243,10 @@ xdr_encode_mon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
         if (IS_ERR(p))
                 return PTR_ERR(p);
 
-        /* Surprise - there may even be room for an IPv6 address now */
-        *p++ = argp->addr;
-        *p++ = 0;
-        *p++ = 0;
-        *p++ = 0;
+        p = xdr_encode_priv(p, argp);
+        if (IS_ERR(p))
+                return PTR_ERR(p);
+
         rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
         return 0;
 }
@@ -265,7 +282,8 @@ xdr_decode_stat(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
 #define SM_my_id_sz     (SM_my_name_sz+3)
 #define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 #define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
-#define SM_mon_sz       (SM_mon_id_sz+4)
+#define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
+#define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 #define SM_monres_sz    2
 #define SM_unmonres_sz  1
 
diff --git a/include/linux/lockd/sm_inter.h b/include/linux/lockd/sm_inter.h
index 22a645828f26..5a5448bdb17d 100644
--- a/include/linux/lockd/sm_inter.h
+++ b/include/linux/lockd/sm_inter.h
@@ -19,6 +19,7 @@
 #define SM_NOTIFY       6
 
 #define SM_MAXSTRLEN    1024
+#define SM_PRIV_SIZE    16
 
 /*
  * Arguments for all calls to statd