nfsd4: callback program number is per-session

The callback program is allowed to depend on the session which the
callback is going over.

No change in behavior yet, while we still only do callbacks over a
single session for the lifetime of the client.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 7f5b267..b3bed36 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -96,7 +96,8 @@
 	/* SETCLIENTID info */
 	struct sockaddr_storage	cb_addr;
 	size_t			cb_addrlen;
-	u32                     cb_prog;
+	u32                     cb_prog; /* used only in 4.0 case;
+					    per-session otherwise */
 	u32			cb_minorversion;
 	u32                     cb_ident;	/* minorversion 0 only */
 	struct svc_xprt		*cb_xprt;	/* minorversion 1 only */
@@ -172,6 +173,7 @@
 	struct nfsd4_channel_attrs se_fchannel;
 	struct nfsd4_channel_attrs se_bchannel;
 	struct list_head	se_conns;
+	u32			se_cb_prog;
 	u32			se_cb_seq_nr;
 	struct nfsd4_slot	*se_slots[];	/* forward channel slots */
 };