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Commit 310c9b91 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
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UPSTREAM: wireguard: send/receive: use explicit unlikely branch instead of implicit coalescing 



It's very unlikely that send will become true. It's nearly always false
between 0 and 120 seconds of a session, and in most cases becomes true
only between 120 and 121 seconds before becoming false again. So,
unlikely(send) is clearly the right option here.

What happened before was that we had this complex boolean expression
with multiple likely and unlikely clauses nested. Since this is
evaluated left-to-right anyway, the whole thing got converted to
unlikely. So, we can clean this up to better represent what's going on.

The generated code is the same.

Suggested-by: default avatarSultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
(cherry picked from commit 243f2148937adc72bcaaa590d482d599c936efde)
Bug: 152722841
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
Change-Id: I0cc67841703296acab0892503d34d3ce84c40ddb
parent e312e6a3

drivers/net/wireguard/receive.c

+6 −7
Original line number Diff line number Diff line
@@ -226,21 +226,20 @@ void wg_packet_handshake_receive_worker(struct work_struct *work) 
static void keep_key_fresh(struct wg_peer *peer)

{

	struct noise_keypair *keypair;

	bool send = false;

	bool send;



	if (peer->sent_lastminute_handshake)

		return;



	rcu_read_lock_bh();

	keypair = rcu_dereference_bh(peer->keypairs.current_keypair);

	if (likely(keypair && READ_ONCE(keypair->sending.is_valid)) &&

	send = keypair && READ_ONCE(keypair->sending.is_valid) &&

	       keypair->i_am_the_initiator &&

	    unlikely(wg_birthdate_has_expired(keypair->sending.birthdate,

			REJECT_AFTER_TIME - KEEPALIVE_TIMEOUT - REKEY_TIMEOUT)))

		send = true;

	       wg_birthdate_has_expired(keypair->sending.birthdate,

			REJECT_AFTER_TIME - KEEPALIVE_TIMEOUT - REKEY_TIMEOUT);

	rcu_read_unlock_bh();



	if (send) {

	if (unlikely(send)) {

		peer->sent_lastminute_handshake = true;

		wg_packet_send_queued_handshake_initiation(peer, false);

	}

drivers/net/wireguard/send.c

+6 −9
Original line number Diff line number Diff line
@@ -124,20 +124,17 @@ void wg_packet_send_handshake_cookie(struct wg_device *wg, 
static void keep_key_fresh(struct wg_peer *peer)

{

	struct noise_keypair *keypair;

	bool send = false;

	bool send;



	rcu_read_lock_bh();

	keypair = rcu_dereference_bh(peer->keypairs.current_keypair);

	if (likely(keypair && READ_ONCE(keypair->sending.is_valid)) &&

	    (unlikely(atomic64_read(&keypair->sending.counter.counter) >

		      REKEY_AFTER_MESSAGES) ||

	send = keypair && READ_ONCE(keypair->sending.is_valid) &&

	       (atomic64_read(&keypair->sending.counter.counter) > REKEY_AFTER_MESSAGES ||

		(keypair->i_am_the_initiator &&

	      unlikely(wg_birthdate_has_expired(keypair->sending.birthdate,

						REKEY_AFTER_TIME)))))

		send = true;

		 wg_birthdate_has_expired(keypair->sending.birthdate, REKEY_AFTER_TIME)));

	rcu_read_unlock_bh();



	if (send)

	if (unlikely(send))

		wg_packet_send_queued_handshake_initiation(peer, false);

}