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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Tariq Toukan <tariqt@mellanox.com>,
        Boris Pismenny <borisp@mellanox.com>,
        "David S . Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 4.14 21/78] net: Do not clear the sock TX queue in sk_set_socket()
Date:   Mon, 29 Jun 2020 11:37:09 -0400
Message-Id: <20200629153806.2494953-22-sashal@kernel.org>
In-Reply-To: <20200629153806.2494953-1-sashal@kernel.org>
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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 c6a003bc4737c..a2e10d0b12804 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1687,7 +1687,6 @@ static inline int sk_tx_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 d2cb2051d0453..08ca2ec0ce60a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1538,6 +1538,7 @@ 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;
@@ -1740,6 +1741,7 @@ 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