ebpf: Refactor tun_rss_steering_prog()

This saves branches and makes later BPF program changes easier.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

tools/ebpf/rss.bpf.c

@@ -547,27 +547,23 @@ int tun_rss_steering_prog(struct __sk_buff *skb)
     config = bpf_map_lookup_elem(&tap_rss_map_configurations, &key);
     toe = bpf_map_lookup_elem(&tap_rss_map_toeplitz_key, &key);
 
-    if (config && toe) {
-        if (!config->redirect) {
-            return config->default_queue;
-        }
+    if (!config || !toe) {
+        return 0;
+    }
 
-        if (calculate_rss_hash(skb, config, toe, &hash)) {
-            __u32 table_idx = hash % config->indirections_len;
-            __u16 *queue = 0;
+    if (config->redirect && calculate_rss_hash(skb, config, toe, &hash)) {
+        __u32 table_idx = hash % config->indirections_len;
+        __u16 *queue = 0;
 
-            queue = bpf_map_lookup_elem(&tap_rss_map_indirection_table,
-                                        &table_idx);
+        queue = bpf_map_lookup_elem(&tap_rss_map_indirection_table,
+                                    &table_idx);
 
-            if (queue) {
-                return *queue;
-            }
+        if (queue) {
+            return *queue;
         }
-
-        return config->default_queue;
     }
 
-    return 0;
+    return config->default_queue;
 }
 
 char _license[] SEC("license") = "GPL v2";