Commit 5bb4c45d authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by David S. Miller
Browse files

net/tls: Read sk_prot once when building tls proto ops 



Apart from being a "tremendous" win when it comes to generated machine
code (see bloat-o-meter output for x86-64 below) this mainly prepares
ground for annotating access to sk_prot with READ_ONCE, so that we don't
pepper the code with access annotations and needlessly repeat loads.

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-46 (-46)
Function                                     old     new   delta
tls_init                                     851     805     -46
Total: Before=21063, After=21017, chg -0.22%

Signed-off-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f13fe3e6

net/tls/tls_main.c

+9 −8
Original line number Diff line number Diff line
@@ -628,24 +628,25 @@ struct tls_context *tls_ctx_create(struct sock *sk) 
static void tls_build_proto(struct sock *sk)

{

	int ip_ver = sk->sk_family == AF_INET6 ? TLSV6 : TLSV4;

	const struct proto *prot = sk->sk_prot;



	/* Build IPv6 TLS whenever the address of tcpv6 _prot changes */

	if (ip_ver == TLSV6 &&

	    unlikely(sk->sk_prot != smp_load_acquire(&saved_tcpv6_prot))) {

	    unlikely(prot != smp_load_acquire(&saved_tcpv6_prot))) {

		mutex_lock(&tcpv6_prot_mutex);

		if (likely(sk->sk_prot != saved_tcpv6_prot)) {

			build_protos(tls_prots[TLSV6], sk->sk_prot);

			smp_store_release(&saved_tcpv6_prot, sk->sk_prot);

		if (likely(prot != saved_tcpv6_prot)) {

			build_protos(tls_prots[TLSV6], prot);

			smp_store_release(&saved_tcpv6_prot, prot);

		}

		mutex_unlock(&tcpv6_prot_mutex);

	}



	if (ip_ver == TLSV4 &&

	    unlikely(sk->sk_prot != smp_load_acquire(&saved_tcpv4_prot))) {

	    unlikely(prot != smp_load_acquire(&saved_tcpv4_prot))) {

		mutex_lock(&tcpv4_prot_mutex);

		if (likely(sk->sk_prot != saved_tcpv4_prot)) {

			build_protos(tls_prots[TLSV4], sk->sk_prot);

			smp_store_release(&saved_tcpv4_prot, sk->sk_prot);

		if (likely(prot != saved_tcpv4_prot)) {

			build_protos(tls_prots[TLSV4], prot);

			smp_store_release(&saved_tcpv4_prot, prot);

		}

		mutex_unlock(&tcpv4_prot_mutex);

	}

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