[PATCH net 0/7] wireguard fixes for 5.12-rc1

[PATCH net 0/7] wireguard fixes for 5.12-rc1

[Jason A. Donenfeld]

Hi Dave,

This series has a collection of fixes that have piled up for a little
while now, that I unfortunately didn't get a chance to send out earlier.

1) Removes unlikely() from IS_ERR(), since it's already implied.

2) Remove a bogus sparse annotation that hasn't been needed for years.

3) Addition test in the test suite for stressing parallel ndo_start_xmit.

4) Slight struct reordering in preparation for subsequent fix.

5) If skb->protocol is bogus, we no longer attempt to send icmp messages.

6) Massive memory usage fix, hit by larger deployments.

7) Fix typo in kconfig dependency logic.

(1) and (2) are tiny cleanups, and (3) is just a test, so if you're
trying to reduce churn, you could not backport these. But (4), (5), (6),
and (7) fix problems and should be applied to stable. IMO, it's probably
easiest to just apply them all to stable.

Thanks,
Jason

Antonio Quartulli (1):
  wireguard: avoid double unlikely() notation when using IS_ERR()

Jann Horn (1):
  wireguard: socket: remove bogus __be32 annotation

Jason A. Donenfeld (5):
  wireguard: selftests: test multiple parallel streams
  wireguard: peer: put frequently used members above cache lines
  wireguard: device: do not generate ICMP for non-IP packets
  wireguard: queueing: get rid of per-peer ring buffers
  wireguard: kconfig: use arm chacha even with no neon

 drivers/net/Kconfig                        |  2 +-
 drivers/net/wireguard/device.c             | 21 +++---
 drivers/net/wireguard/device.h             | 15 ++--
 drivers/net/wireguard/peer.c               | 28 +++----
 drivers/net/wireguard/peer.h               |  8 +-
 drivers/net/wireguard/queueing.c           | 86 +++++++++++++++++-----
 drivers/net/wireguard/queueing.h           | 45 ++++++++---
 drivers/net/wireguard/receive.c            | 16 ++--
 drivers/net/wireguard/send.c               | 31 +++-----
 drivers/net/wireguard/socket.c             |  8 +-
 tools/testing/selftests/wireguard/netns.sh | 15 +++-
 11 files changed, 170 insertions(+), 105 deletions(-)

-- 
2.30.1

[PATCH net 1/7] wireguard: avoid double unlikely() notation when using IS_ERR()

[Jason A. Donenfeld]

From: Antonio Quartulli <a@unstable.cc>

The definition of IS_ERR() already applies the unlikely() notation
when checking the error status of the passed pointer. For this
reason there is no need to have the same notation outside of
IS_ERR() itself.

Clean up code by removing redundant notation.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/device.c | 2 +-
 drivers/net/wireguard/socket.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c
index a3ed49cd95c3..cd51a2afa28e 100644
--- a/drivers/net/wireguard/device.c
+++ b/drivers/net/wireguard/device.c
@@ -157,7 +157,7 @@ static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 	} else {
 		struct sk_buff *segs = skb_gso_segment(skb, 0);
 
-		if (unlikely(IS_ERR(segs))) {
+		if (IS_ERR(segs)) {
 			ret = PTR_ERR(segs);
 			goto err_peer;
 		}
diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index 410b318e57fb..41430c0e465a 100644
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c
@@ -71,7 +71,7 @@ static int send4(struct wg_device *wg, struct sk_buff *skb,
 				ip_rt_put(rt);
 			rt = ip_route_output_flow(sock_net(sock), &fl, sock);
 		}
-		if (unlikely(IS_ERR(rt))) {
+		if (IS_ERR(rt)) {
 			ret = PTR_ERR(rt);
 			net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
 					    wg->dev->name, &endpoint->addr, ret);
@@ -138,7 +138,7 @@ static int send6(struct wg_device *wg, struct sk_buff *skb,
 		}
 		dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sock), sock, &fl,
 						      NULL);
-		if (unlikely(IS_ERR(dst))) {
+		if (IS_ERR(dst)) {
 			ret = PTR_ERR(dst);
 			net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
 					    wg->dev->name, &endpoint->addr, ret);
-- 
2.30.1

[PATCH net 2/7] wireguard: socket: remove bogus __be32 annotation

[Jason A. Donenfeld]

From: Jann Horn <jannh@google.com>

The endpoint->src_if4 has nothing to do with fixed-endian numbers; remove
the bogus annotation.

This was introduced in
https://git.zx2c4.com/wireguard-monolithic-historical/commit?id=14e7d0a499a676ec55176c0de2f9fcbd34074a82
in the historical WireGuard repo because the old code used to
zero-initialize multiple members as follows:

    endpoint->src4.s_addr = endpoint->src_if4 = fl.saddr = 0;

Because fl.saddr is fixed-endian and an assignment returns a value with the
type of its left operand, this meant that sparse detected an assignment
between values of different endianness.

Since then, this assignment was already split up into separate statements;
just the cast survived.

Signed-off-by: Jann Horn <jannh@google.com>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index 41430c0e465a..d9ad850daa79 100644
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c
@@ -53,7 +53,7 @@ static int send4(struct wg_device *wg, struct sk_buff *skb,
 		if (unlikely(!inet_confirm_addr(sock_net(sock), NULL, 0,
 						fl.saddr, RT_SCOPE_HOST))) {
 			endpoint->src4.s_addr = 0;
-			*(__force __be32 *)&endpoint->src_if4 = 0;
+			endpoint->src_if4 = 0;
 			fl.saddr = 0;
 			if (cache)
 				dst_cache_reset(cache);
@@ -63,7 +63,7 @@ static int send4(struct wg_device *wg, struct sk_buff *skb,
 			     PTR_ERR(rt) == -EINVAL) || (!IS_ERR(rt) &&
 			     rt->dst.dev->ifindex != endpoint->src_if4)))) {
 			endpoint->src4.s_addr = 0;
-			*(__force __be32 *)&endpoint->src_if4 = 0;
+			endpoint->src_if4 = 0;
 			fl.saddr = 0;
 			if (cache)
 				dst_cache_reset(cache);
-- 
2.30.1

[PATCH net 3/7] wireguard: selftests: test multiple parallel streams

[Jason A. Donenfeld]

In order to test ndo_start_xmit being called in parallel, explicitly add
separate tests, which should all run on different cores. This should
help tease out bugs associated with queueing up packets from different
cores in parallel. Currently, it hasn't found those types of bugs, but
given future planned work, this is a useful regression to avoid.

Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/wireguard/netns.sh | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/wireguard/netns.sh b/tools/testing/selftests/wireguard/netns.sh
index 74c69b75f6f5..7ed7cd95e58f 100755
--- a/tools/testing/selftests/wireguard/netns.sh
+++ b/tools/testing/selftests/wireguard/netns.sh
@@ -39,7 +39,7 @@ ip0() { pretty 0 "ip $*"; ip -n $netns0 "$@"; }
 ip1() { pretty 1 "ip $*"; ip -n $netns1 "$@"; }
 ip2() { pretty 2 "ip $*"; ip -n $netns2 "$@"; }
 sleep() { read -t "$1" -N 1 || true; }
-waitiperf() { pretty "${1//*-}" "wait for iperf:5201 pid $2"; while [[ $(ss -N "$1" -tlpH 'sport = 5201') != *\"iperf3\",pid=$2,fd=* ]]; do sleep 0.1; done; }
+waitiperf() { pretty "${1//*-}" "wait for iperf:${3:-5201} pid $2"; while [[ $(ss -N "$1" -tlpH "sport = ${3:-5201}") != *\"iperf3\",pid=$2,fd=* ]]; do sleep 0.1; done; }
 waitncatudp() { pretty "${1//*-}" "wait for udp:1111 pid $2"; while [[ $(ss -N "$1" -ulpH 'sport = 1111') != *\"ncat\",pid=$2,fd=* ]]; do sleep 0.1; done; }
 waitiface() { pretty "${1//*-}" "wait for $2 to come up"; ip netns exec "$1" bash -c "while [[ \$(< \"/sys/class/net/$2/operstate\") != up ]]; do read -t .1 -N 0 || true; done;"; }
 
@@ -141,6 +141,19 @@ tests() {
 	n2 iperf3 -s -1 -B fd00::2 &
 	waitiperf $netns2 $!
 	n1 iperf3 -Z -t 3 -b 0 -u -c fd00::2
+
+	# TCP over IPv4, in parallel
+	for max in 4 5 50; do
+		local pids=( )
+		for ((i=0; i < max; ++i)) do
+			n2 iperf3 -p $(( 5200 + i )) -s -1 -B 192.168.241.2 &
+			pids+=( $! ); waitiperf $netns2 $! $(( 5200 + i ))
+		done
+		for ((i=0; i < max; ++i)) do
+			n1 iperf3 -Z -t 3 -p $(( 5200 + i )) -c 192.168.241.2 &
+		done
+		wait "${pids[@]}"
+	done
 }
 
 [[ $(ip1 link show dev wg0) =~ mtu\ ([0-9]+) ]] && orig_mtu="${BASH_REMATCH[1]}"
-- 
2.30.1

[PATCH net 4/7] wireguard: peer: put frequently used members above cache lines

[Jason A. Donenfeld]

The is_dead boolean is checked for every single packet, while the
internal_id member is used basically only for pr_debug messages. So it
makes sense to hoist up is_dead into some space formerly unused by a
struct hole, while demoting internal_api to below the lowest struct
cache line.

Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/peer.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireguard/peer.h b/drivers/net/wireguard/peer.h
index 23af40922997..aaff8de6e34b 100644
--- a/drivers/net/wireguard/peer.h
+++ b/drivers/net/wireguard/peer.h
@@ -39,6 +39,7 @@ struct wg_peer {
 	struct crypt_queue tx_queue, rx_queue;
 	struct sk_buff_head staged_packet_queue;
 	int serial_work_cpu;
+	bool is_dead;
 	struct noise_keypairs keypairs;
 	struct endpoint endpoint;
 	struct dst_cache endpoint_cache;
@@ -61,9 +62,8 @@ struct wg_peer {
 	struct rcu_head rcu;
 	struct list_head peer_list;
 	struct list_head allowedips_list;
-	u64 internal_id;
 	struct napi_struct napi;
-	bool is_dead;
+	u64 internal_id;
 };
 
 struct wg_peer *wg_peer_create(struct wg_device *wg,
-- 
2.30.1

[PATCH net 5/7] wireguard: device: do not generate ICMP for non-IP packets

[Jason A. Donenfeld]

If skb->protocol doesn't match the actual skb->data header, it's
probably not a good idea to pass it off to icmp{,v6}_ndo_send, which is
expecting to reply to a valid IP packet. So this commit has that early
mismatch case jump to a later error label.

Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/device.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c
index cd51a2afa28e..8502e1b083ff 100644
--- a/drivers/net/wireguard/device.c
+++ b/drivers/net/wireguard/device.c
@@ -138,7 +138,7 @@ static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 		else if (skb->protocol == htons(ETH_P_IPV6))
 			net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n",
 					    dev->name, &ipv6_hdr(skb)->daddr);
-		goto err;
+		goto err_icmp;
 	}
 
 	family = READ_ONCE(peer->endpoint.addr.sa_family);
@@ -201,12 +201,13 @@ static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 
 err_peer:
 	wg_peer_put(peer);
-err:
-	++dev->stats.tx_errors;
+err_icmp:
 	if (skb->protocol == htons(ETH_P_IP))
 		icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 	else if (skb->protocol == htons(ETH_P_IPV6))
 		icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
+err:
+	++dev->stats.tx_errors;
 	kfree_skb(skb);
 	return ret;
 }
-- 
2.30.1

[PATCH net 6/7] wireguard: queueing: get rid of per-peer ring buffers

[Jason A. Donenfeld]

Having two ring buffers per-peer means that every peer results in two
massive ring allocations. On an 8-core x86_64 machine, this commit
reduces the per-peer allocation from 18,688 bytes to 1,856 bytes, which
is an 90% reduction. Ninety percent! With some single-machine
deployments approaching 500,000 peers, we're talking about a reduction
from 7 gigs of memory down to 700 megs of memory.

In order to get rid of these per-peer allocations, this commit switches
to using a list-based queueing approach. Currently GSO fragments are
chained together using the skb->next pointer (the skb_list_* singly
linked list approach), so we form the per-peer queue around the unused
skb->prev pointer (which sort of makes sense because the links are
pointing backwards). Use of skb_queue_* is not possible here, because
that is based on doubly linked lists and spinlocks. Multiple cores can
write into the queue at any given time, because its writes occur in the
start_xmit path or in the udp_recv path. But reads happen in a single
workqueue item per-peer, amounting to a multi-producer, single-consumer
paradigm.

The MPSC queue is implemented locklessly and never blocks. However, it
is not linearizable (though it is serializable), with a very tight and
unlikely race on writes, which, when hit (some tiny fraction of the
0.15% of partial adds on a fully loaded 16-core x86_64 system), causes
the queue reader to terminate early. However, because every packet sent
queues up the same workqueue item after it is fully added, the worker
resumes again, and stopping early isn't actually a problem, since at
that point the packet wouldn't have yet been added to the encryption
queue. These properties allow us to avoid disabling interrupts or
spinning. The design is based on Dmitry Vyukov's algorithm [1].

Performance-wise, ordinarily list-based queues aren't preferable to
ringbuffers, because of cache misses when following pointers around.
However, we *already* have to follow the adjacent pointers when working
through fragments, so there shouldn't actually be any change there. A
potential downside is that dequeueing is a bit more complicated, but the
ptr_ring structure used prior had a spinlock when dequeueing, so all and
all the difference appears to be a wash.

Actually, from profiling, the biggest performance hit, by far, of this
commit winds up being atomic_add_unless(count, 1, max) and atomic_
dec(count), which account for the majority of CPU time, according to
perf. In that sense, the previous ring buffer was superior in that it
could check if it was full by head==tail, which the list-based approach
cannot do.

But all and all, this enables us to get massive memory savings, allowing
WireGuard to scale for real world deployments, without taking much of a
performance hit.

[1] http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue

Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/device.c   | 12 ++---
 drivers/net/wireguard/device.h   | 15 +++---
 drivers/net/wireguard/peer.c     | 28 ++++-------
 drivers/net/wireguard/peer.h     |  4 +-
 drivers/net/wireguard/queueing.c | 86 +++++++++++++++++++++++++-------
 drivers/net/wireguard/queueing.h | 45 ++++++++++++-----
 drivers/net/wireguard/receive.c  | 16 +++---
 drivers/net/wireguard/send.c     | 31 ++++--------
 8 files changed, 144 insertions(+), 93 deletions(-)

diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c
index 8502e1b083ff..551ddaaaf540 100644
--- a/drivers/net/wireguard/device.c
+++ b/drivers/net/wireguard/device.c
@@ -235,8 +235,8 @@ static void wg_destruct(struct net_device *dev)
 	destroy_workqueue(wg->handshake_receive_wq);
 	destroy_workqueue(wg->handshake_send_wq);
 	destroy_workqueue(wg->packet_crypt_wq);
-	wg_packet_queue_free(&wg->decrypt_queue, true);
-	wg_packet_queue_free(&wg->encrypt_queue, true);
+	wg_packet_queue_free(&wg->decrypt_queue);
+	wg_packet_queue_free(&wg->encrypt_queue);
 	rcu_barrier(); /* Wait for all the peers to be actually freed. */
 	wg_ratelimiter_uninit();
 	memzero_explicit(&wg->static_identity, sizeof(wg->static_identity));
@@ -338,12 +338,12 @@ static int wg_newlink(struct net *src_net, struct net_device *dev,
 		goto err_destroy_handshake_send;
 
 	ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker,
-				   true, MAX_QUEUED_PACKETS);
+				   MAX_QUEUED_PACKETS);
 	if (ret < 0)
 		goto err_destroy_packet_crypt;
 
 	ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker,
-				   true, MAX_QUEUED_PACKETS);
+				   MAX_QUEUED_PACKETS);
 	if (ret < 0)
 		goto err_free_encrypt_queue;
 
@@ -368,9 +368,9 @@ static int wg_newlink(struct net *src_net, struct net_device *dev,
 err_uninit_ratelimiter:
 	wg_ratelimiter_uninit();
 err_free_decrypt_queue:
-	wg_packet_queue_free(&wg->decrypt_queue, true);
+	wg_packet_queue_free(&wg->decrypt_queue);
 err_free_encrypt_queue:
-	wg_packet_queue_free(&wg->encrypt_queue, true);
+	wg_packet_queue_free(&wg->encrypt_queue);
 err_destroy_packet_crypt:
 	destroy_workqueue(wg->packet_crypt_wq);
 err_destroy_handshake_send:
diff --git a/drivers/net/wireguard/device.h b/drivers/net/wireguard/device.h
index 4d0144e16947..854bc3d97150 100644
--- a/drivers/net/wireguard/device.h
+++ b/drivers/net/wireguard/device.h
@@ -27,13 +27,14 @@ struct multicore_worker {
 
 struct crypt_queue {
 	struct ptr_ring ring;
-	union {
-		struct {
-			struct multicore_worker __percpu *worker;
-			int last_cpu;
-		};
-		struct work_struct work;
-	};
+	struct multicore_worker __percpu *worker;
+	int last_cpu;
+};
+
+struct prev_queue {
+	struct sk_buff *head, *tail, *peeked;
+	struct { struct sk_buff *next, *prev; } empty; // Match first 2 members of struct sk_buff.
+	atomic_t count;
 };
 
 struct wg_device {
diff --git a/drivers/net/wireguard/peer.c b/drivers/net/wireguard/peer.c
index b3b6370e6b95..cd5cb0292cb6 100644
--- a/drivers/net/wireguard/peer.c
+++ b/drivers/net/wireguard/peer.c
@@ -32,27 +32,22 @@ struct wg_peer *wg_peer_create(struct wg_device *wg,
 	peer = kzalloc(sizeof(*peer), GFP_KERNEL);
 	if (unlikely(!peer))
 		return ERR_PTR(ret);
-	peer->device = wg;
+	if (dst_cache_init(&peer->endpoint_cache, GFP_KERNEL))
+		goto err;
 
+	peer->device = wg;
 	wg_noise_handshake_init(&peer->handshake, &wg->static_identity,
 				public_key, preshared_key, peer);
-	if (dst_cache_init(&peer->endpoint_cache, GFP_KERNEL))
-		goto err_1;
-	if (wg_packet_queue_init(&peer->tx_queue, wg_packet_tx_worker, false,
-				 MAX_QUEUED_PACKETS))
-		goto err_2;
-	if (wg_packet_queue_init(&peer->rx_queue, NULL, false,
-				 MAX_QUEUED_PACKETS))
-		goto err_3;
-
 	peer->internal_id = atomic64_inc_return(&peer_counter);
 	peer->serial_work_cpu = nr_cpumask_bits;
 	wg_cookie_init(&peer->latest_cookie);
 	wg_timers_init(peer);
 	wg_cookie_checker_precompute_peer_keys(peer);
 	spin_lock_init(&peer->keypairs.keypair_update_lock);
-	INIT_WORK(&peer->transmit_handshake_work,
-		  wg_packet_handshake_send_worker);
+	INIT_WORK(&peer->transmit_handshake_work, wg_packet_handshake_send_worker);
+	INIT_WORK(&peer->transmit_packet_work, wg_packet_tx_worker);
+	wg_prev_queue_init(&peer->tx_queue);
+	wg_prev_queue_init(&peer->rx_queue);
 	rwlock_init(&peer->endpoint_lock);
 	kref_init(&peer->refcount);
 	skb_queue_head_init(&peer->staged_packet_queue);
@@ -68,11 +63,7 @@ struct wg_peer *wg_peer_create(struct wg_device *wg,
 	pr_debug("%s: Peer %llu created\n", wg->dev->name, peer->internal_id);
 	return peer;
 
-err_3:
-	wg_packet_queue_free(&peer->tx_queue, false);
-err_2:
-	dst_cache_destroy(&peer->endpoint_cache);
-err_1:
+err:
 	kfree(peer);
 	return ERR_PTR(ret);
 }
@@ -197,8 +188,7 @@ static void rcu_release(struct rcu_head *rcu)
 	struct wg_peer *peer = container_of(rcu, struct wg_peer, rcu);
 
 	dst_cache_destroy(&peer->endpoint_cache);
-	wg_packet_queue_free(&peer->rx_queue, false);
-	wg_packet_queue_free(&peer->tx_queue, false);
+	WARN_ON(wg_prev_queue_peek(&peer->tx_queue) || wg_prev_queue_peek(&peer->rx_queue));
 
 	/* The final zeroing takes care of clearing any remaining handshake key
 	 * material and other potentially sensitive information.
diff --git a/drivers/net/wireguard/peer.h b/drivers/net/wireguard/peer.h
index aaff8de6e34b..8d53b687a1d1 100644
--- a/drivers/net/wireguard/peer.h
+++ b/drivers/net/wireguard/peer.h
@@ -36,7 +36,7 @@ struct endpoint {
 
 struct wg_peer {
 	struct wg_device *device;
-	struct crypt_queue tx_queue, rx_queue;
+	struct prev_queue tx_queue, rx_queue;
 	struct sk_buff_head staged_packet_queue;
 	int serial_work_cpu;
 	bool is_dead;
@@ -46,7 +46,7 @@ struct wg_peer {
 	rwlock_t endpoint_lock;
 	struct noise_handshake handshake;
 	atomic64_t last_sent_handshake;
-	struct work_struct transmit_handshake_work, clear_peer_work;
+	struct work_struct transmit_handshake_work, clear_peer_work, transmit_packet_work;
 	struct cookie latest_cookie;
 	struct hlist_node pubkey_hash;
 	u64 rx_bytes, tx_bytes;
diff --git a/drivers/net/wireguard/queueing.c b/drivers/net/wireguard/queueing.c
index 71b8e80b58e1..48e7b982a307 100644
--- a/drivers/net/wireguard/queueing.c
+++ b/drivers/net/wireguard/queueing.c
@@ -9,8 +9,7 @@ struct multicore_worker __percpu *
 wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr)
 {
 	int cpu;
-	struct multicore_worker __percpu *worker =
-		alloc_percpu(struct multicore_worker);
+	struct multicore_worker __percpu *worker = alloc_percpu(struct multicore_worker);
 
 	if (!worker)
 		return NULL;
@@ -23,7 +22,7 @@ wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr)
 }
 
 int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
-			 bool multicore, unsigned int len)
+			 unsigned int len)
 {
 	int ret;
 
@@ -31,25 +30,78 @@ int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
 	ret = ptr_ring_init(&queue->ring, len, GFP_KERNEL);
 	if (ret)
 		return ret;
-	if (function) {
-		if (multicore) {
-			queue->worker = wg_packet_percpu_multicore_worker_alloc(
-				function, queue);
-			if (!queue->worker) {
-				ptr_ring_cleanup(&queue->ring, NULL);
-				return -ENOMEM;
-			}
-		} else {
-			INIT_WORK(&queue->work, function);
-		}
+	queue->worker = wg_packet_percpu_multicore_worker_alloc(function, queue);
+	if (!queue->worker) {
+		ptr_ring_cleanup(&queue->ring, NULL);
+		return -ENOMEM;
 	}
 	return 0;
 }
 
-void wg_packet_queue_free(struct crypt_queue *queue, bool multicore)
+void wg_packet_queue_free(struct crypt_queue *queue)
 {
-	if (multicore)
-		free_percpu(queue->worker);
+	free_percpu(queue->worker);
 	WARN_ON(!__ptr_ring_empty(&queue->ring));
 	ptr_ring_cleanup(&queue->ring, NULL);
 }
+
+#define NEXT(skb) ((skb)->prev)
+#define STUB(queue) ((struct sk_buff *)&queue->empty)
+
+void wg_prev_queue_init(struct prev_queue *queue)
+{
+	NEXT(STUB(queue)) = NULL;
+	queue->head = queue->tail = STUB(queue);
+	queue->peeked = NULL;
+	atomic_set(&queue->count, 0);
+	BUILD_BUG_ON(
+		offsetof(struct sk_buff, next) != offsetof(struct prev_queue, empty.next) -
+							offsetof(struct prev_queue, empty) ||
+		offsetof(struct sk_buff, prev) != offsetof(struct prev_queue, empty.prev) -
+							 offsetof(struct prev_queue, empty));
+}
+
+static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
+{
+	WRITE_ONCE(NEXT(skb), NULL);
+	WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
+}
+
+bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
+{
+	if (!atomic_add_unless(&queue->count, 1, MAX_QUEUED_PACKETS))
+		return false;
+	__wg_prev_queue_enqueue(queue, skb);
+	return true;
+}
+
+struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue)
+{
+	struct sk_buff *tail = queue->tail, *next = smp_load_acquire(&NEXT(tail));
+
+	if (tail == STUB(queue)) {
+		if (!next)
+			return NULL;
+		queue->tail = next;
+		tail = next;
+		next = smp_load_acquire(&NEXT(next));
+	}
+	if (next) {
+		queue->tail = next;
+		atomic_dec(&queue->count);
+		return tail;
+	}
+	if (tail != READ_ONCE(queue->head))
+		return NULL;
+	__wg_prev_queue_enqueue(queue, STUB(queue));
+	next = smp_load_acquire(&NEXT(tail));
+	if (next) {
+		queue->tail = next;
+		atomic_dec(&queue->count);
+		return tail;
+	}
+	return NULL;
+}
+
+#undef NEXT
+#undef STUB
diff --git a/drivers/net/wireguard/queueing.h b/drivers/net/wireguard/queueing.h
index dfb674e03076..4ef2944a68bc 100644
--- a/drivers/net/wireguard/queueing.h
+++ b/drivers/net/wireguard/queueing.h
@@ -17,12 +17,13 @@ struct wg_device;
 struct wg_peer;
 struct multicore_worker;
 struct crypt_queue;
+struct prev_queue;
 struct sk_buff;
 
 /* queueing.c APIs: */
 int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
-			 bool multicore, unsigned int len);
-void wg_packet_queue_free(struct crypt_queue *queue, bool multicore);
+			 unsigned int len);
+void wg_packet_queue_free(struct crypt_queue *queue);
 struct multicore_worker __percpu *
 wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr);
 
@@ -135,8 +136,31 @@ static inline int wg_cpumask_next_online(int *next)
 	return cpu;
 }
 
+void wg_prev_queue_init(struct prev_queue *queue);
+
+/* Multi producer */
+bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb);
+
+/* Single consumer */
+struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue);
+
+/* Single consumer */
+static inline struct sk_buff *wg_prev_queue_peek(struct prev_queue *queue)
+{
+	if (queue->peeked)
+		return queue->peeked;
+	queue->peeked = wg_prev_queue_dequeue(queue);
+	return queue->peeked;
+}
+
+/* Single consumer */
+static inline void wg_prev_queue_drop_peeked(struct prev_queue *queue)
+{
+	queue->peeked = NULL;
+}
+
 static inline int wg_queue_enqueue_per_device_and_peer(
-	struct crypt_queue *device_queue, struct crypt_queue *peer_queue,
+	struct crypt_queue *device_queue, struct prev_queue *peer_queue,
 	struct sk_buff *skb, struct workqueue_struct *wq, int *next_cpu)
 {
 	int cpu;
@@ -145,8 +169,9 @@ static inline int wg_queue_enqueue_per_device_and_peer(
 	/* We first queue this up for the peer ingestion, but the consumer
 	 * will wait for the state to change to CRYPTED or DEAD before.
 	 */
-	if (unlikely(ptr_ring_produce_bh(&peer_queue->ring, skb)))
+	if (unlikely(!wg_prev_queue_enqueue(peer_queue, skb)))
 		return -ENOSPC;
+
 	/* Then we queue it up in the device queue, which consumes the
 	 * packet as soon as it can.
 	 */
@@ -157,9 +182,7 @@ static inline int wg_queue_enqueue_per_device_and_peer(
 	return 0;
 }
 
-static inline void wg_queue_enqueue_per_peer(struct crypt_queue *queue,
-					     struct sk_buff *skb,
-					     enum packet_state state)
+static inline void wg_queue_enqueue_per_peer_tx(struct sk_buff *skb, enum packet_state state)
 {
 	/* We take a reference, because as soon as we call atomic_set, the
 	 * peer can be freed from below us.
@@ -167,14 +190,12 @@ static inline void wg_queue_enqueue_per_peer(struct crypt_queue *queue,
 	struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
 
 	atomic_set_release(&PACKET_CB(skb)->state, state);
-	queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu,
-					       peer->internal_id),
-		      peer->device->packet_crypt_wq, &queue->work);
+	queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu, peer->internal_id),
+		      peer->device->packet_crypt_wq, &peer->transmit_packet_work);
 	wg_peer_put(peer);
 }
 
-static inline void wg_queue_enqueue_per_peer_napi(struct sk_buff *skb,
-						  enum packet_state state)
+static inline void wg_queue_enqueue_per_peer_rx(struct sk_buff *skb, enum packet_state state)
 {
 	/* We take a reference, because as soon as we call atomic_set, the
 	 * peer can be freed from below us.
diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c
index 2c9551ea6dc7..7dc84bcca261 100644
--- a/drivers/net/wireguard/receive.c
+++ b/drivers/net/wireguard/receive.c
@@ -444,7 +444,6 @@ static void wg_packet_consume_data_done(struct wg_peer *peer,
 int wg_packet_rx_poll(struct napi_struct *napi, int budget)
 {
 	struct wg_peer *peer = container_of(napi, struct wg_peer, napi);
-	struct crypt_queue *queue = &peer->rx_queue;
 	struct noise_keypair *keypair;
 	struct endpoint endpoint;
 	enum packet_state state;
@@ -455,11 +454,10 @@ int wg_packet_rx_poll(struct napi_struct *napi, int budget)
 	if (unlikely(budget <= 0))
 		return 0;
 
-	while ((skb = __ptr_ring_peek(&queue->ring)) != NULL &&
+	while ((skb = wg_prev_queue_peek(&peer->rx_queue)) != NULL &&
 	       (state = atomic_read_acquire(&PACKET_CB(skb)->state)) !=
 		       PACKET_STATE_UNCRYPTED) {
-		__ptr_ring_discard_one(&queue->ring);
-		peer = PACKET_PEER(skb);
+		wg_prev_queue_drop_peeked(&peer->rx_queue);
 		keypair = PACKET_CB(skb)->keypair;
 		free = true;
 
@@ -508,7 +506,7 @@ void wg_packet_decrypt_worker(struct work_struct *work)
 		enum packet_state state =
 			likely(decrypt_packet(skb, PACKET_CB(skb)->keypair)) ?
 				PACKET_STATE_CRYPTED : PACKET_STATE_DEAD;
-		wg_queue_enqueue_per_peer_napi(skb, state);
+		wg_queue_enqueue_per_peer_rx(skb, state);
 		if (need_resched())
 			cond_resched();
 	}
@@ -531,12 +529,10 @@ static void wg_packet_consume_data(struct wg_device *wg, struct sk_buff *skb)
 	if (unlikely(READ_ONCE(peer->is_dead)))
 		goto err;
 
-	ret = wg_queue_enqueue_per_device_and_peer(&wg->decrypt_queue,
-						   &peer->rx_queue, skb,
-						   wg->packet_crypt_wq,
-						   &wg->decrypt_queue.last_cpu);
+	ret = wg_queue_enqueue_per_device_and_peer(&wg->decrypt_queue, &peer->rx_queue, skb,
+						   wg->packet_crypt_wq, &wg->decrypt_queue.last_cpu);
 	if (unlikely(ret == -EPIPE))
-		wg_queue_enqueue_per_peer_napi(skb, PACKET_STATE_DEAD);
+		wg_queue_enqueue_per_peer_rx(skb, PACKET_STATE_DEAD);
 	if (likely(!ret || ret == -EPIPE)) {
 		rcu_read_unlock_bh();
 		return;
diff --git a/drivers/net/wireguard/send.c b/drivers/net/wireguard/send.c
index f74b9341ab0f..5368f7c35b4b 100644
--- a/drivers/net/wireguard/send.c
+++ b/drivers/net/wireguard/send.c
@@ -239,8 +239,7 @@ void wg_packet_send_keepalive(struct wg_peer *peer)
 	wg_packet_send_staged_packets(peer);
 }
 
-static void wg_packet_create_data_done(struct sk_buff *first,
-				       struct wg_peer *peer)
+static void wg_packet_create_data_done(struct wg_peer *peer, struct sk_buff *first)
 {
 	struct sk_buff *skb, *next;
 	bool is_keepalive, data_sent = false;
@@ -262,22 +261,19 @@ static void wg_packet_create_data_done(struct sk_buff *first,
 
 void wg_packet_tx_worker(struct work_struct *work)
 {
-	struct crypt_queue *queue = container_of(work, struct crypt_queue,
-						 work);
+	struct wg_peer *peer = container_of(work, struct wg_peer, transmit_packet_work);
 	struct noise_keypair *keypair;
 	enum packet_state state;
 	struct sk_buff *first;
-	struct wg_peer *peer;
 
-	while ((first = __ptr_ring_peek(&queue->ring)) != NULL &&
+	while ((first = wg_prev_queue_peek(&peer->tx_queue)) != NULL &&
 	       (state = atomic_read_acquire(&PACKET_CB(first)->state)) !=
 		       PACKET_STATE_UNCRYPTED) {
-		__ptr_ring_discard_one(&queue->ring);
-		peer = PACKET_PEER(first);
+		wg_prev_queue_drop_peeked(&peer->tx_queue);
 		keypair = PACKET_CB(first)->keypair;
 
 		if (likely(state == PACKET_STATE_CRYPTED))
-			wg_packet_create_data_done(first, peer);
+			wg_packet_create_data_done(peer, first);
 		else
 			kfree_skb_list(first);
 
@@ -306,16 +302,14 @@ void wg_packet_encrypt_worker(struct work_struct *work)
 				break;
 			}
 		}
-		wg_queue_enqueue_per_peer(&PACKET_PEER(first)->tx_queue, first,
-					  state);
+		wg_queue_enqueue_per_peer_tx(first, state);
 		if (need_resched())
 			cond_resched();
 	}
 }
 
-static void wg_packet_create_data(struct sk_buff *first)
+static void wg_packet_create_data(struct wg_peer *peer, struct sk_buff *first)
 {
-	struct wg_peer *peer = PACKET_PEER(first);
 	struct wg_device *wg = peer->device;
 	int ret = -EINVAL;
 
@@ -323,13 +317,10 @@ static void wg_packet_create_data(struct sk_buff *first)
 	if (unlikely(READ_ONCE(peer->is_dead)))
 		goto err;
 
-	ret = wg_queue_enqueue_per_device_and_peer(&wg->encrypt_queue,
-						   &peer->tx_queue, first,
-						   wg->packet_crypt_wq,
-						   &wg->encrypt_queue.last_cpu);
+	ret = wg_queue_enqueue_per_device_and_peer(&wg->encrypt_queue, &peer->tx_queue, first,
+						   wg->packet_crypt_wq, &wg->encrypt_queue.last_cpu);
 	if (unlikely(ret == -EPIPE))
-		wg_queue_enqueue_per_peer(&peer->tx_queue, first,
-					  PACKET_STATE_DEAD);
+		wg_queue_enqueue_per_peer_tx(first, PACKET_STATE_DEAD);
 err:
 	rcu_read_unlock_bh();
 	if (likely(!ret || ret == -EPIPE))
@@ -393,7 +384,7 @@ void wg_packet_send_staged_packets(struct wg_peer *peer)
 	packets.prev->next = NULL;
 	wg_peer_get(keypair->entry.peer);
 	PACKET_CB(packets.next)->keypair = keypair;
-	wg_packet_create_data(packets.next);
+	wg_packet_create_data(peer, packets.next);
 	return;
 
 out_invalid:
-- 
2.30.1

[PATCH net 7/7] wireguard: kconfig: use arm chacha even with no neon

[Jason A. Donenfeld]

The condition here was incorrect: a non-neon fallback implementation is
available on arm32 when NEON is not supported.

Reported-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 260f9f46668b..63339d29be90 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -87,7 +87,7 @@ config WIREGUARD
 	select CRYPTO_CURVE25519_X86 if X86 && 64BIT
 	select ARM_CRYPTO if ARM
 	select ARM64_CRYPTO if ARM64
-	select CRYPTO_CHACHA20_NEON if (ARM || ARM64) && KERNEL_MODE_NEON
+	select CRYPTO_CHACHA20_NEON if ARM || (ARM64 && KERNEL_MODE_NEON)
 	select CRYPTO_POLY1305_NEON if ARM64 && KERNEL_MODE_NEON
 	select CRYPTO_POLY1305_ARM if ARM
 	select CRYPTO_CURVE25519_NEON if ARM && KERNEL_MODE_NEON
-- 
2.30.1

Re: [PATCH net 0/7] wireguard fixes for 5.12-rc1

[Jakub Kicinski]

On Mon, 22 Feb 2021 17:25:42 +0100 Jason A. Donenfeld wrote:
> This series has a collection of fixes that have piled up for a little
> while now, that I unfortunately didn't get a chance to send out earlier.
> 
> 1) Removes unlikely() from IS_ERR(), since it's already implied.
> 
> 2) Remove a bogus sparse annotation that hasn't been needed for years.
> 
> 3) Addition test in the test suite for stressing parallel ndo_start_xmit.
> 
> 4) Slight struct reordering in preparation for subsequent fix.
> 
> 5) If skb->protocol is bogus, we no longer attempt to send icmp messages.
> 
> 6) Massive memory usage fix, hit by larger deployments.
> 
> 7) Fix typo in kconfig dependency logic.
> 
> (1) and (2) are tiny cleanups, and (3) is just a test, so if you're
> trying to reduce churn, you could not backport these. But (4), (5), (6),
> and (7) fix problems and should be applied to stable. IMO, it's probably
> easiest to just apply them all to stable.

Preferably 1, 2, 4 and 6 should go into net-next first, and not be
posted half way through the merge window, but I trust you had them 
well tested so applied, thanks!