datapath: Drop port information from odp_stats.

As with n_flows, n_ports was used regularly by userspace to determine how
much memory to allocate when listing ports, but it is no longer needed for
that.  max_ports, on the other hand, is necessary but it is also a fixed
value for the kernel datapath right now and if we expand it we can also
come up with a way to report the expanded value.

The remaining members of odp_stats are actually real statistics that I
intend to keep.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

datapath/datapath.c

@@ -370,7 +370,6 @@ static struct vport *new_vport(const struct vport_parms *parms)
 
 		rcu_assign_pointer(dp->ports[parms->port_no], vport);
 		list_add_rcu(&vport->node, &dp->port_list);
-		dp->n_ports++;
 
 		dp_ifinfo_notify(RTM_NEWLINK, vport);
 	}
@@ -390,7 +389,6 @@ int dp_detach_port(struct vport *p)
 	dp_ifinfo_notify(RTM_DELLINK, p);
 
 	/* First drop references to device. */
-	p->dp->n_ports--;
 	list_del_rcu(&p->node);
 	rcu_assign_pointer(p->dp->ports[p->port_no], NULL);
 
@@ -1202,8 +1200,6 @@ static int get_dp_stats(struct datapath *dp, struct odp_stats __user *statsp)
 	struct odp_stats stats;
 	int i;
 
-	stats.n_ports = dp->n_ports;
-	stats.max_ports = DP_MAX_PORTS;
 	stats.n_frags = stats.n_hit = stats.n_missed = stats.n_lost = 0;
 	for_each_possible_cpu(i) {
 		const struct dp_stats_percpu *percpu_stats;

datapath/datapath.h

@@ -68,7 +68,6 @@ struct dp_stats_percpu {
  * @waitqueue: Waitqueue, for waiting for new packets in @queues.
  * @n_flows: Number of flows currently in flow table.
  * @table: Current flow table.
- * @n_ports: Number of ports currently in @ports.
  * @ports: Map from port number to &struct vport.  %ODPP_LOCAL port
  * always exists, other ports may be %NULL.
  * @port_list: List of all ports in @ports in arbitrary order.
@@ -93,7 +92,6 @@ struct datapath {
 	struct tbl __rcu *table;
 
 	/* Switch ports. */
-	unsigned int n_ports;
 	struct vport __rcu *ports[DP_MAX_PORTS];
 	struct list_head port_list;
 

include/openvswitch/datapath-protocol.h

@@ -100,11 +100,6 @@
 #define ODP_GET_SFLOW_PROBABILITY _IOW('O', 20, int)
 
 struct odp_stats {
-    /* Ports. */
-    uint32_t n_ports;           /* Current number of ports. */
-    uint32_t max_ports;         /* Maximum supported number of ports. */
-
-    /* Lookups. */
     uint64_t n_frags;           /* Number of dropped IP fragments. */
     uint64_t n_hit;             /* Number of flow table matches. */
     uint64_t n_missed;          /* Number of flow table misses. */

lib/dpif-linux.c

@@ -365,6 +365,14 @@ dpif_linux_port_query_by_name(const struct dpif *dpif, const char *devname,
     return dpif_linux_port_query__(dpif, 0, devname, dpif_port);
 }
 
+static int
+dpif_linux_get_max_ports(const struct dpif *dpif OVS_UNUSED)
+{
+    /* If the datapath increases its range of supported ports, then it should
+     * start reporting that. */
+    return 1024;
+}
+
 static int
 dpif_linux_flow_flush(struct dpif *dpif_)
 {
@@ -681,6 +689,7 @@ const struct dpif_class dpif_linux_class = {
     dpif_linux_port_del,
     dpif_linux_port_query_by_number,
     dpif_linux_port_query_by_name,
+    dpif_linux_get_max_ports,
     dpif_linux_port_dump_start,
     dpif_linux_port_dump_next,
     dpif_linux_port_dump_done,

lib/dpif-netdev.c

@@ -302,8 +302,6 @@ dpif_netdev_get_stats(const struct dpif *dpif, struct odp_stats *stats)
 {
     struct dp_netdev *dp = get_dp_netdev(dpif);
     memset(stats, 0, sizeof *stats);
-    stats->n_ports = dp->n_ports;
-    stats->max_ports = MAX_PORTS;
     stats->n_frags = dp->n_frags;
     stats->n_hit = dp->n_hit;
     stats->n_missed = dp->n_missed;
@@ -512,6 +510,12 @@ dpif_netdev_port_query_by_name(const struct dpif *dpif, const char *devname,
     return error;
 }
 
+static int
+dpif_netdev_get_max_ports(const struct dpif *dpif OVS_UNUSED)
+{
+    return MAX_PORTS;
+}
+
 static void
 dp_netdev_free_flow(struct dp_netdev *dp, struct dp_netdev_flow *flow)
 {
@@ -1393,6 +1397,7 @@ const struct dpif_class dpif_netdev_class = {
     dpif_netdev_port_del,
     dpif_netdev_port_query_by_number,
     dpif_netdev_port_query_by_name,
+    dpif_netdev_get_max_ports,
     dpif_netdev_port_dump_start,
     dpif_netdev_port_dump_next,
     dpif_netdev_port_dump_done,

lib/dpif-provider.h

@@ -156,6 +156,10 @@ struct dpif_class {
     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
                               struct dpif_port *port);
 
+    /* Returns one greater than the largest port number accepted in flow
+     * actions. */
+    int (*get_max_ports)(const struct dpif *dpif);
+
     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
      * and initializes '*statep' with any data needed for iteration.  On
      * failure, returns a positive errno value. */

lib/dpif.c

@@ -561,6 +561,14 @@ dpif_port_query_by_name(const struct dpif *dpif, const char *devname,
     return error;
 }
 
+/* Returns one greater than the maximum port number accepted in flow
+ * actions. */
+int
+dpif_get_max_ports(const struct dpif *dpif)
+{
+    return dpif->dpif_class->get_max_ports(dpif);
+}
+
 /* Looks up port number 'port_no' in 'dpif'.  On success, returns 0 and copies
  * the port's name into the 'name_size' bytes in 'name', ensuring that the
  * result is null-terminated.  On failure, returns a positive errno value and

lib/dpif.h

@@ -80,6 +80,7 @@ int dpif_port_query_by_name(const struct dpif *, const char *devname,
                             struct dpif_port *);
 int dpif_port_get_name(struct dpif *, uint16_t port_no,
                        char *name, size_t name_size);
+int dpif_get_max_ports(const struct dpif *);
 
 struct dpif_port_dump {
     const struct dpif *dpif;

ofproto/ofproto.c

@@ -429,7 +429,6 @@ ofproto_create(const char *datapath, const char *datapath_type,
                const struct ofhooks *ofhooks, void *aux,
                struct ofproto **ofprotop)
 {
-    struct odp_stats stats;
     struct ofproto *p;
     struct dpif *dpif;
     int error;
@@ -444,13 +443,6 @@ ofproto_create(const char *datapath, const char *datapath_type,
         VLOG_ERR("failed to open datapath %s: %s", datapath, strerror(error));
         return error;
     }
-    error = dpif_get_dp_stats(dpif, &stats);
-    if (error) {
-        VLOG_ERR("failed to obtain stats for datapath %s: %s",
-                 datapath, strerror(error));
-        dpif_close(dpif);
-        return error;
-    }
     error = dpif_recv_set_mask(dpif, ODPL_MISS | ODPL_ACTION | ODPL_SFLOW);
     if (error) {
         VLOG_ERR("failed to listen on datapath %s: %s",
@@ -476,7 +468,7 @@ ofproto_create(const char *datapath, const char *datapath_type,
     p->netdev_monitor = netdev_monitor_create();
     hmap_init(&p->ports);
     shash_init(&p->port_by_name);
-    p->max_ports = stats.max_ports;
+    p->max_ports = dpif_get_max_ports(dpif);
 
     /* Initialize submodules. */
     p->switch_status = switch_status_create(p);

utilities/ovs-dpctl.c

@@ -338,8 +338,6 @@ show_dpif(struct dpif *dpif)
 
     printf("%s:\n", dpif_name(dpif));
     if (!dpif_get_dp_stats(dpif, &stats)) {
-        printf("\tports: cur:%"PRIu32", max:%"PRIu32"\n",
-               stats.n_ports, stats.max_ports);
         printf("\tlookups: frags:%llu, hit:%llu, missed:%llu, lost:%llu\n",
                (unsigned long long int) stats.n_frags,
                (unsigned long long int) stats.n_hit,