Merge branch 'ovs-upcall-issues'

Mark Gray says:

====================
openvswitch: per-cpu upcall patchwork issues

Some issues were raised by patchwork at:
https://patchwork.kernel.org/project/netdevbpf/patch/20210630095350.817785-1-mark.d.gray@redhat.com/#24285159
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/openvswitch.h

@@ -70,7 +70,7 @@ enum ovs_datapath_cmd {
  * set on the datapath port (for OVS_ACTION_ATTR_MISS).  Only valid on
  * %OVS_DP_CMD_NEW requests. A value of zero indicates that upcalls should
  * not be sent.
- * OVS_DP_ATTR_PER_CPU_PIDS: Per-cpu array of PIDs for upcalls when
+ * @OVS_DP_ATTR_PER_CPU_PIDS: Per-cpu array of PIDs for upcalls when
  * OVS_DP_F_DISPATCH_UPCALL_PER_CPU feature is set.
  * @OVS_DP_ATTR_STATS: Statistics about packets that have passed through the
  * datapath.  Always present in notifications.
@@ -89,8 +89,8 @@ enum ovs_datapath_attr {
 	OVS_DP_ATTR_USER_FEATURES,	/* OVS_DP_F_*  */
 	OVS_DP_ATTR_PAD,
 	OVS_DP_ATTR_MASKS_CACHE_SIZE,
-	OVS_DP_ATTR_PER_CPU_PIDS,   /* Netlink PIDS to receive upcalls in per-cpu
-				     * dispatch mode
+	OVS_DP_ATTR_PER_CPU_PIDS,   /* Netlink PIDS to receive upcalls in
+				     * per-cpu dispatch mode
 				     */
 	__OVS_DP_ATTR_MAX
 };

net/openvswitch/actions.c

@@ -924,9 +924,11 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 			break;
 
 		case OVS_USERSPACE_ATTR_PID:
-			if (dp->user_features & OVS_DP_F_DISPATCH_UPCALL_PER_CPU)
+			if (dp->user_features &
+			    OVS_DP_F_DISPATCH_UPCALL_PER_CPU)
 				upcall.portid =
-				   ovs_dp_get_upcall_portid(dp, smp_processor_id());
+				  ovs_dp_get_upcall_portid(dp,
+							   smp_processor_id());
 			else
 				upcall.portid = nla_get_u32(a);
 			break;

net/openvswitch/datapath.c

@@ -168,7 +168,7 @@ static void destroy_dp_rcu(struct rcu_head *rcu)
 	free_percpu(dp->stats_percpu);
 	kfree(dp->ports);
 	ovs_meters_exit(dp);
-	kfree(dp->upcall_portids);
+	kfree(rcu_dereference_raw(dp->upcall_portids));
 	kfree(dp);
 }
 
@@ -244,7 +244,8 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)
 		upcall.cmd = OVS_PACKET_CMD_MISS;
 
 		if (dp->user_features & OVS_DP_F_DISPATCH_UPCALL_PER_CPU)
-			upcall.portid = ovs_dp_get_upcall_portid(dp, smp_processor_id());
+			upcall.portid =
+			    ovs_dp_get_upcall_portid(dp, smp_processor_id());
 		else
 			upcall.portid = ovs_vport_find_upcall_portid(p, skb);
 
@@ -1636,13 +1637,16 @@ u32 ovs_dp_get_upcall_portid(const struct datapath *dp, uint32_t cpu_id)
 	if (dp_nlsk_pids) {
 		if (cpu_id < dp_nlsk_pids->n_pids) {
 			return dp_nlsk_pids->pids[cpu_id];
-		} else if (dp_nlsk_pids->n_pids > 0 && cpu_id >= dp_nlsk_pids->n_pids) {
-			/* If the number of netlink PIDs is mismatched with the number of
-			 * CPUs as seen by the kernel, log this and send the upcall to an
-			 * arbitrary socket (0) in order to not drop packets
+		} else if (dp_nlsk_pids->n_pids > 0 &&
+			   cpu_id >= dp_nlsk_pids->n_pids) {
+			/* If the number of netlink PIDs is mismatched with
+			 * the number of CPUs as seen by the kernel, log this
+			 * and send the upcall to an arbitrary socket (0) in
+			 * order to not drop packets
 			 */
 			pr_info_ratelimited("cpu_id mismatch with handler threads");
-			return dp_nlsk_pids->pids[cpu_id % dp_nlsk_pids->n_pids];
+			return dp_nlsk_pids->pids[cpu_id %
+						  dp_nlsk_pids->n_pids];
 		} else {
 			return 0;
 		}