NFS: Make trace_nfs4_setup_sequence() available to NFS v4.0

This tracepoint displays information about the slot that was chosen for
the RPC, in addition to session information.  This could be useful
information for debugging, and we can set the session id hash to 0 to
indicate that there is no session.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4proc.c

@@ -924,11 +924,9 @@ int nfs4_setup_sequence(const struct nfs_client *client,
 		res->sr_timestamp = jiffies;
 		res->sr_status_flags = 0;
 		res->sr_status = 1;
-#ifdef CONFIG_NFS_V4_1
-		trace_nfs4_setup_sequence(session, args);
-#endif /* CONFIG_NFS_V4_1 */
 	}
 
+	trace_nfs4_setup_sequence(session, args);
 out_start:
 	rpc_call_start(task);
 	return 0;

fs/nfs/nfs4session.h

@@ -175,6 +175,8 @@ static inline int nfs4_has_persistent_session(const struct nfs_client *clp)
 	return 0;
 }
 
+#define nfs_session_id_hash(session) (0)
+
 #endif /* defined(CONFIG_NFS_V4_1) */
 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
 #endif /* __LINUX_FS_NFS_NFS4SESSION_H */

fs/nfs/nfs4trace.h

@@ -241,38 +241,6 @@ DEFINE_NFS4_CLIENTID_EVENT(nfs4_bind_conn_to_session);
 DEFINE_NFS4_CLIENTID_EVENT(nfs4_sequence);
 DEFINE_NFS4_CLIENTID_EVENT(nfs4_reclaim_complete);
 
-TRACE_EVENT(nfs4_setup_sequence,
-		TP_PROTO(
-			const struct nfs4_session *session,
-			const struct nfs4_sequence_args *args
-		),
-		TP_ARGS(session, args),
-
-		TP_STRUCT__entry(
-			__field(unsigned int, session)
-			__field(unsigned int, slot_nr)
-			__field(unsigned int, seq_nr)
-			__field(unsigned int, highest_used_slotid)
-		),
-
-		TP_fast_assign(
-			const struct nfs4_slot *sa_slot = args->sa_slot;
-			__entry->session = nfs_session_id_hash(&session->sess_id);
-			__entry->slot_nr = sa_slot->slot_nr;
-			__entry->seq_nr = sa_slot->seq_nr;
-			__entry->highest_used_slotid =
-					sa_slot->table->highest_used_slotid;
-		),
-		TP_printk(
-			"session=0x%08x slot_nr=%u seq_nr=%u "
-			"highest_used_slotid=%u",
-			__entry->session,
-			__entry->slot_nr,
-			__entry->seq_nr,
-			__entry->highest_used_slotid
-		)
-);
-
 #define show_nfs4_sequence_status_flags(status) \
 	__print_flags((unsigned long)status, "|", \
 		{ SEQ4_STATUS_CB_PATH_DOWN, "CB_PATH_DOWN" }, \
@@ -382,6 +350,38 @@ TRACE_EVENT(nfs4_cb_sequence,
 );
 #endif /* CONFIG_NFS_V4_1 */
 
+TRACE_EVENT(nfs4_setup_sequence,
+		TP_PROTO(
+			const struct nfs4_session *session,
+			const struct nfs4_sequence_args *args
+		),
+		TP_ARGS(session, args),
+
+		TP_STRUCT__entry(
+			__field(unsigned int, session)
+			__field(unsigned int, slot_nr)
+			__field(unsigned int, seq_nr)
+			__field(unsigned int, highest_used_slotid)
+		),
+
+		TP_fast_assign(
+			const struct nfs4_slot *sa_slot = args->sa_slot;
+			__entry->session = session ? nfs_session_id_hash(&session->sess_id) : 0;
+			__entry->slot_nr = sa_slot->slot_nr;
+			__entry->seq_nr = sa_slot->seq_nr;
+			__entry->highest_used_slotid =
+					sa_slot->table->highest_used_slotid;
+		),
+		TP_printk(
+			"session=0x%08x slot_nr=%u seq_nr=%u "
+			"highest_used_slotid=%u",
+			__entry->session,
+			__entry->slot_nr,
+			__entry->seq_nr,
+			__entry->highest_used_slotid
+		)
+);
+
 DECLARE_EVENT_CLASS(nfs4_open_event,
 		TP_PROTO(
 			const struct nfs_open_context *ctx,