[PATCH 4.19 039/131] net: Do not clear the sock TX queue in sk_set_socket()

Sasha Levin
2020-06-29T19:36:05Z

From: Tariq Toukan <tariqt@mellanox.com>

[ Upstream commit 41b14fb8724d5a4b382a63cb4a1a61880347ccb8 ]

Clearing the sock TX queue in sk_set_socket() might cause unexpected
out-of-order transmit when called from sock_orphan(), as outstanding
packets can pick a different TX queue and bypass the ones already queued.

This is undesired in general. More specifically, it breaks the in-order
scheduling property guarantee for device-offloaded TLS sockets.

Remove the call to sk_tx_queue_clear() in sk_set_socket(), and add it
explicitly only where needed.

Fixes: e022f0b4a03f ("net: Introduce sk_tx_queue_mapping")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/sock.h | 1 -
net/core/sock.c | 2 ++
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index f359e5c947628..e2df102e669e8 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1775,7 +1775,6 @@ static inline int sk_rx_queue_get(const struct sock *sk)

static inline void sk_set_socket(struct sock *sk, struct socket *sock)
{
- sk_tx_queue_clear(sk);
sk->sk_socket = sock;
}

diff --git a/net/core/sock.c b/net/core/sock.c
index b11d116383dab..8721264a2b394 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1540,6 +1540,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
cgroup_sk_alloc(&sk->sk_cgrp_data);
sock_update_classid(&sk->sk_cgrp_data);
sock_update_netprioidx(&sk->sk_cgrp_data);
+ sk_tx_queue_clear(sk);
}

return sk;
@@ -1747,6 +1748,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
*/
sk_refcnt_debug_inc(newsk);
sk_set_socket(newsk, NULL);
+ sk_tx_queue_clear(newsk);
newsk->sk_wq = NULL;

if (newsk->sk_prot->sockets_allocated)
--
2.25.1