[ovs-dev] [PATCH v3 2/4] netdev-offload: Add "offload-driver" other_config to specify offload driver

[Toshiaki Makita]

The following commit will introduce another offload driver using XDP.
When using afxdp netdev, both of TC and XDP will be supported, so let's
add an other_config to specify which offload driver is preferable.
When not specified and multiple offload drivers can be used, TC will be
used if netdev supports it.

Signed-off-by: Toshiaki Makita <toshiaki.makita1 at gmail.com>
---
 lib/netdev-offload.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/lib/netdev-offload.c b/lib/netdev-offload.c
index ab97a292e..669513646 100644
--- a/lib/netdev-offload.c
+++ b/lib/netdev-offload.c
@@ -60,6 +60,9 @@ VLOG_DEFINE_THIS_MODULE(netdev_offload);
 
 static bool netdev_flow_api_enabled = false;
 
+#define FLOW_API_DRIVER_DEFAULT "linux_tc"
+static const char *netdev_flow_api_driver = NULL;
+
 /* Protects 'netdev_flow_apis'.  */
 static struct ovs_mutex netdev_flow_api_provider_mutex = OVS_MUTEX_INITIALIZER;
 
@@ -171,18 +174,30 @@ netdev_flow_api_equals(const struct netdev *netdev1,
 static int
 netdev_assign_flow_api(struct netdev *netdev)
 {
-    struct netdev_registered_flow_api *rfa;
+    struct netdev_registered_flow_api *rfa, *current_rfa = NULL;
 
     CMAP_FOR_EACH (rfa, cmap_node, &netdev_flow_apis) {
+        if (netdev_flow_api_driver &&
+            strcmp(netdev_flow_api_driver, rfa->flow_api->type)) {
+            continue;
+        }
         if (!rfa->flow_api->init_flow_api(netdev)) {
-            ovs_refcount_ref(&rfa->refcnt);
-            ovsrcu_set(&netdev->flow_api, rfa->flow_api);
-            VLOG_INFO("%s: Assigned flow API '%s'.",
-                      netdev_get_name(netdev), rfa->flow_api->type);
-            return 0;
+            if (!current_rfa ||
+                (!netdev_flow_api_driver &&
+                 !strcmp(FLOW_API_DRIVER_DEFAULT, rfa->flow_api->type))) {
+                current_rfa = rfa;
+            }
+        } else {
+            VLOG_DBG("%s: flow API '%s' is not suitable.",
+                     netdev_get_name(netdev), rfa->flow_api->type);
         }
-        VLOG_DBG("%s: flow API '%s' is not suitable.",
-                 netdev_get_name(netdev), rfa->flow_api->type);
+    }
+    if (current_rfa) {
+        ovs_refcount_ref(&current_rfa->refcnt);
+        ovsrcu_set(&netdev->flow_api, current_rfa->flow_api);
+        VLOG_INFO("%s: Assigned flow API '%s'.",
+                  netdev_get_name(netdev), current_rfa->flow_api->type);
+        return 0;
     }
     VLOG_INFO("%s: No suitable flow API found.", netdev_get_name(netdev));
 
@@ -649,6 +664,8 @@ netdev_set_flow_api_enabled(const struct smap *ovs_other_config)
         static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
 
         if (ovsthread_once_start(&once)) {
+            const char *offload_driver;
+
             netdev_flow_api_enabled = true;
 
             VLOG_INFO("netdev: Flow API Enabled");
@@ -662,6 +679,10 @@ netdev_set_flow_api_enabled(const struct smap *ovs_other_config)
                 netdev_offload_rebalance_policy = true;
             }
 
+            offload_driver = smap_get_def(ovs_other_config, "offload-driver",
+                                          NULL);
+            netdev_flow_api_driver = nullable_xstrdup(offload_driver);
+
             netdev_ports_flow_init();
 
             ovsthread_once_done(&once);
-- 
2.25.1