net: add add indirect call wrapper in skb_release_head_state()

While stress testing UDP senders on a host with expensive indirect
calls, I found cpus processing TX completions where showing
a very high cost (20%) in sock_wfree() due to
CONFIG_MITIGATION_RETPOLINE=y.

Take care of TCP and UDP TX destructors and use INDIRECT_CALL_3() macro.

Signed-off-by: Eric Dumazet <[e-mail]>
Reviewed-by: Kuniyuki Iwashima <[e-mail]>
Reviewed-by: Toke Høiland-Jørgensen <[e-mail]>
Tested-by: Jamal Hadi Salim <[e-mail]>
Acked-by: Jamal Hadi Salim <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/core/skbuff.c

···
 	skb_dst_drop(skb);
 	if (skb->destructor) {
 		DEBUG_NET_WARN_ON_ONCE(in_hardirq());
-		skb->destructor(skb);
+#ifdef CONFIG_INET
+		INDIRECT_CALL_3(skb->destructor,
+				tcp_wfree, __sock_wfree, sock_wfree,
+				skb);
+#else
+		INDIRECT_CALL_1(skb->destructor,
+				sock_wfree,
+				skb);
+
+#endif
 	}
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	nf_conntrack_put(skb_nfct(skb));