Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Denis Drozdov <denisd@mellanox.com>,
        Leon Romanovsky <leonro@mellanox.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 035/131] IB/IPoIB: Set ah valid flag in multicast
 send flow
Thread-Topic: [PATCH AUTOSEL 4.18 035/131] IB/IPoIB: Set ah valid flag in
 multicast send flow
Thread-Index: AQHUQr1fjuLgdoktXkO6dn2F9eeAoA==
Date:   Sun, 2 Sep 2018 13:03:41 +0000
Message-ID: <20180902064601.183036-35-alexander.levin@microsoft.com>
References: <20180902064601.183036-1-alexander.levin@microsoft.com>
In-Reply-To: <20180902064601.183036-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 1e547389-1bf1-4175-e47b-08d610d491d5
X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Sep 2018 13:03:41.6647
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0135
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Denis Drozdov <denisd@mellanox.com>

[ Upstream commit 75da96067ade4e7854379ec2f7834f3497652b1a ]

The change of ipoib_ah data structure with adding "valid" flag and
checks of ah->valid in ipoib_start_xmit affected multicast packet flow.

Since the multicast flow doesn't invoke path_rec_start, "ah->valid" flag
remains unset, so that ipoib_start_xmit end up with neigh_refresh_path
instead of sending the packet using neigh.

"ah->valid" has to be set in multicast send flow. As a result IPoIB
starts sending packets via neigh immediately and eliminates 60sec delay
of neigh keep alive interval.

The typical example of this issue are two sequential arpings:

arping 11.134.208.9 -> got response (mcast_send)
arping 11.134.208.9 -> no response  (ah->valid =3D 0)

Fixes: fa9391dbad4b ("RDMA/ipoib: Update paths on CLIENT_REREG/SM_CHANGE ev=
ents")
Signed-off-by: Denis Drozdov <denisd@mellanox.com>
Reviewed-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infin=
iband/ulp/ipoib/ipoib_multicast.c
index 6709328d90f8..c7e034963738 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -822,6 +822,7 @@ void ipoib_mcast_send(struct net_device *dev, u8 *daddr=
, struct sk_buff *skb)
 			if (neigh && list_empty(&neigh->list)) {
 				kref_get(&mcast->ah->ref);
 				neigh->ah	=3D mcast->ah;
+				neigh->ah->valid =3D 1;
 				list_add_tail(&neigh->list, &mcast->neigh_list);
 			}
 		}
--=20
2.17.1