From: Jakub Sitnicki <jakub@cloudflare.com>
Date: Tue, 17 Mar 2020 18:04:38 +0100
Subject: net/tls: Read sk_prot once when building tls proto ops
Patch-mainline: v5.7-rc1
Git-commit: 5bb4c45d466cb28dd0a7f15f80c4cb7768054e94
References: bsc#1176447
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: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/tls/tls_main.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -628,24 +628,25 @@ struct tls_context *tls_ctx_create(struc
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);
}