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Date:   Wed, 27 Sep 2023 20:17:40 +0800
From:   Dust Li <dust.li@linux.alibaba.com>
To:     Leon Romanovsky <leon@kernel.org>
Cc:     Albert Huang <huangjie.albert@bytedance.com>,
        Karsten Graul <kgraul@linux.ibm.com>,
        Wenjia Zhang <wenjia@linux.ibm.com>,
        Jan Karcher <jaka@linux.ibm.com>,
        "D. Wythe" <alibuda@linux.alibaba.com>,
        Tony Lu <tonylu@linux.alibaba.com>,
        Wen Gu <guwen@linux.alibaba.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] net/smc: add support for netdevice in
 containers.
Message-ID: <20230927121740.GF92403@linux.alibaba.com>
Reply-To: dust.li@linux.alibaba.com
References: <20230925023546.9964-1-huangjie.albert@bytedance.com>
 <20230927034209.GE92403@linux.alibaba.com>
 <20230927055528.GP1642130@unreal>
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In-Reply-To: <20230927055528.GP1642130@unreal>
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On Wed, Sep 27, 2023 at 08:55:28AM +0300, Leon Romanovsky wrote:
>On Wed, Sep 27, 2023 at 11:42:09AM +0800, Dust Li wrote:
>> On Mon, Sep 25, 2023 at 10:35:45AM +0800, Albert Huang wrote:
>> >If the netdevice is within a container and communicates externally
>> >through network technologies like VXLAN, we won't be able to find
>> >routing information in the init_net namespace. To address this issue,
>> 
>> Thanks for your founding !
>> 
>> I think this is a more generic problem, but not just related to VXLAN ?
>> If we use SMC-R v2 and the netdevice is in a net namespace which is not
>> init_net, we should always fail, right ? If so, I'd prefer this to be a bugfix.
>
>BTW, does this patch take into account net namespace of ib_device?

I think this patch is irrelevant with the netns of ib_device.

SMC has a global smc_ib_devices list reported by ib_client, and checked
the netns using rdma_dev_access_netns. So I think we should have handled
that well.

Best regards,
Dust

>
>Thanks
>
>> 
>> Best regards,
>> Dust
>> 
>> >we need to add a struct net parameter to the smc_ib_find_route function.
>> >This allow us to locate the routing information within the corresponding
>> >net namespace, ensuring the correct completion of the SMC CLC interaction.
>> >
>> >Signed-off-by: Albert Huang <huangjie.albert@bytedance.com>
>> >---
>> > net/smc/af_smc.c | 3 ++-
>> > net/smc/smc_ib.c | 7 ++++---
>> > net/smc/smc_ib.h | 2 +-
>> > 3 files changed, 7 insertions(+), 5 deletions(-)
>> >
>> >diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
>> >index bacdd971615e..7a874da90c7f 100644
>> >--- a/net/smc/af_smc.c
>> >+++ b/net/smc/af_smc.c
>> >@@ -1201,6 +1201,7 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
>> > 		(struct smc_clc_msg_accept_confirm_v2 *)aclc;
>> > 	struct smc_clc_first_contact_ext *fce =
>> > 		smc_get_clc_first_contact_ext(clc_v2, false);
>> >+	struct net *net = sock_net(&smc->sk);
>> > 	int rc;
>> > 
>> > 	if (!ini->first_contact_peer || aclc->hdr.version == SMC_V1)
>> >@@ -1210,7 +1211,7 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
>> > 		memcpy(ini->smcrv2.nexthop_mac, &aclc->r0.lcl.mac, ETH_ALEN);
>> > 		ini->smcrv2.uses_gateway = false;
>> > 	} else {
>> >-		if (smc_ib_find_route(smc->clcsock->sk->sk_rcv_saddr,
>> >+		if (smc_ib_find_route(net, smc->clcsock->sk->sk_rcv_saddr,
>> > 				      smc_ib_gid_to_ipv4(aclc->r0.lcl.gid),
>> > 				      ini->smcrv2.nexthop_mac,
>> > 				      &ini->smcrv2.uses_gateway))
>> >diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
>> >index 9b66d6aeeb1a..89981dbe46c9 100644
>> >--- a/net/smc/smc_ib.c
>> >+++ b/net/smc/smc_ib.c
>> >@@ -193,7 +193,7 @@ bool smc_ib_port_active(struct smc_ib_device *smcibdev, u8 ibport)
>> > 	return smcibdev->pattr[ibport - 1].state == IB_PORT_ACTIVE;
>> > }
>> > 
>> >-int smc_ib_find_route(__be32 saddr, __be32 daddr,
>> >+int smc_ib_find_route(struct net *net, __be32 saddr, __be32 daddr,
>> > 		      u8 nexthop_mac[], u8 *uses_gateway)
>> > {
>> > 	struct neighbour *neigh = NULL;
>> >@@ -205,7 +205,7 @@ int smc_ib_find_route(__be32 saddr, __be32 daddr,
>> > 
>> > 	if (daddr == cpu_to_be32(INADDR_NONE))
>> > 		goto out;
>> >-	rt = ip_route_output_flow(&init_net, &fl4, NULL);
>> >+	rt = ip_route_output_flow(net, &fl4, NULL);
>> > 	if (IS_ERR(rt))
>> > 		goto out;
>> > 	if (rt->rt_uses_gateway && rt->rt_gw_family != AF_INET)
>> >@@ -235,6 +235,7 @@ static int smc_ib_determine_gid_rcu(const struct net_device *ndev,
>> > 	if (smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE_UDP_ENCAP &&
>> > 	    smc_ib_gid_to_ipv4((u8 *)&attr->gid) != cpu_to_be32(INADDR_NONE)) {
>> > 		struct in_device *in_dev = __in_dev_get_rcu(ndev);
>> >+		struct net *net = dev_net(ndev);
>> > 		const struct in_ifaddr *ifa;
>> > 		bool subnet_match = false;
>> > 
>> >@@ -248,7 +249,7 @@ static int smc_ib_determine_gid_rcu(const struct net_device *ndev,
>> > 		}
>> > 		if (!subnet_match)
>> > 			goto out;
>> >-		if (smcrv2->daddr && smc_ib_find_route(smcrv2->saddr,
>> >+		if (smcrv2->daddr && smc_ib_find_route(net, smcrv2->saddr,
>> > 						       smcrv2->daddr,
>> > 						       smcrv2->nexthop_mac,
>> > 						       &smcrv2->uses_gateway))
>> >diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
>> >index 4df5f8c8a0a1..ef8ac2b7546d 100644
>> >--- a/net/smc/smc_ib.h
>> >+++ b/net/smc/smc_ib.h
>> >@@ -112,7 +112,7 @@ void smc_ib_sync_sg_for_device(struct smc_link *lnk,
>> > int smc_ib_determine_gid(struct smc_ib_device *smcibdev, u8 ibport,
>> > 			 unsigned short vlan_id, u8 gid[], u8 *sgid_index,
>> > 			 struct smc_init_info_smcrv2 *smcrv2);
>> >-int smc_ib_find_route(__be32 saddr, __be32 daddr,
>> >+int smc_ib_find_route(struct net *net, __be32 saddr, __be32 daddr,
>> > 		      u8 nexthop_mac[], u8 *uses_gateway);
>> > bool smc_ib_is_valid_local_systemid(void);
>> > int smcr_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb);
>> >-- 
>> >2.37.1 (Apple Git-137.1)
>>