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From:   Guangguan Wang <guangguan.wang@linux.alibaba.com>
To:     wenjia@linux.ibm.com, jaka@linux.ibm.com, kgraul@linux.ibm.com,
        tonylu@linux.alibaba.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com
Cc:     alibuda@linux.alibaba.com, guwen@linux.alibaba.com,
        linux-s390@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [RFC PATCH net-next 5/6] net/smc: support max links per lgr negotiation in clc handshake
Date:   Thu,  3 Aug 2023 21:24:21 +0800
Message-Id: <20230803132422.6280-6-guangguan.wang@linux.alibaba.com>
In-Reply-To: <20230803132422.6280-1-guangguan.wang@linux.alibaba.com>
References: <20230803132422.6280-1-guangguan.wang@linux.alibaba.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Support max links per lgr negotiation in clc handshake for SMCR v2.1,
which is one of smc v2.1 features.

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
---
 net/smc/af_smc.c   | 44 +++++++++++++++++++++++++++-----------------
 net/smc/smc_clc.c  | 16 +++++++++++++++-
 net/smc/smc_clc.h  |  7 +++++--
 net/smc/smc_core.c |  5 +++++
 net/smc/smc_core.h |  5 +++++
 net/smc/smc_llc.c  | 17 +++++++++++++----
 6 files changed, 70 insertions(+), 24 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index b95d3fd48c28..23384d08d3f2 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -610,20 +610,22 @@ static int smcr_clnt_conf_first_link(struct smc_sock *smc)
 	smc_llc_link_active(link);
 	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
 
-	/* optional 2nd link, receive ADD LINK request from server */
-	qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
-			      SMC_LLC_ADD_LINK);
-	if (!qentry) {
-		struct smc_clc_msg_decline dclc;
-
-		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
-				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
-		if (rc == -EAGAIN)
-			rc = 0; /* no DECLINE received, go with one link */
-		return rc;
+	if (link->lgr->max_links > 1) {
+		/* optional 2nd link, receive ADD LINK request from server */
+		qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
+				      SMC_LLC_ADD_LINK);
+		if (!qentry) {
+			struct smc_clc_msg_decline dclc;
+
+			rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+					      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
+			if (rc == -EAGAIN)
+				rc = 0; /* no DECLINE received, go with one link */
+			return rc;
+		}
+		smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
+		smc_llc_cli_add_link(link, qentry);
 	}
-	smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
-	smc_llc_cli_add_link(link, qentry);
 	return 0;
 }
 
@@ -1215,6 +1217,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
 	memcpy(ini->peer_gid, aclc->r0.lcl.gid, SMC_GID_SIZE);
 	memcpy(ini->peer_mac, aclc->r0.lcl.mac, ETH_ALEN);
 	ini->max_conns = SMC_RMBS_PER_LGR_MAX;
+	ini->max_links = SMC_LINKS_ADD_LNK_MAX;
 
 	reason_code = smc_connect_rdma_v2_prepare(smc, aclc, ini);
 	if (reason_code)
@@ -1861,10 +1864,12 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
 	smc_llc_link_active(link);
 	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
 
-	down_write(&link->lgr->llc_conf_mutex);
-	/* initial contact - try to establish second link */
-	smc_llc_srv_add_link(link, NULL);
-	up_write(&link->lgr->llc_conf_mutex);
+	if (link->lgr->max_links > 1) {
+		down_write(&link->lgr->llc_conf_mutex);
+		/* initial contact - try to establish second link */
+		smc_llc_srv_add_link(link, NULL);
+		up_write(&link->lgr->llc_conf_mutex);
+	}
 	return 0;
 }
 
@@ -2468,6 +2473,11 @@ static void smc_listen_work(struct work_struct *work)
 		goto out_decl;
 	}
 
+	/* fce smc release version is needed in smc_listen_rdma_finish,
+	 * so save fce info here.
+	 */
+	smc_conn_save_peer_info_fce(new_smc, cclc);
+
 	/* finish worker */
 	if (!ini->is_smcd) {
 		rc = smc_listen_rdma_finish(new_smc, cclc,
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 5e90234df189..66b6d2dc98a8 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -433,8 +433,10 @@ static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
 	}
 
 	if (ini->release_ver >= SMC_RELEASE_1) {
-		if (!ini->is_smcd)
+		if (!ini->is_smcd) {
 			fce->max_conns = ini->max_conns;
+			fce->max_links = ini->max_links;
+		}
 	}
 
 out:
@@ -942,6 +944,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 	if (smcr_indicated(ini->smc_type_v2)) {
 		memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
 		v2_ext->max_conns = SMC_CONN_PER_LGR_MAX;
+		v2_ext->max_links = SMC_LINKS_PER_LGR_MAX_PREFER;
 	}
 
 	pclc_base->hdr.length = htons(plen);
@@ -1177,6 +1180,7 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
 	 * which is the default value in smc v1 and v2.0.
 	 */
 	ini->max_conns = SMC_RMBS_PER_LGR_MAX;
+	ini->max_links = SMC_LINKS_ADD_LNK_MAX;
 
 	if ((!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) ||
 	    ini->release_ver < SMC_RELEASE_1)
@@ -1190,6 +1194,10 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
 		ini->max_conns = min_t(u8, pclc_v2_ext->max_conns, SMC_CONN_PER_LGR_MAX);
 		if (!ini->max_conns)
 			return SMC_CLC_DECL_MAXCONNERR;
+
+		ini->max_links = min_t(u8, pclc_v2_ext->max_links, SMC_LINKS_PER_LGR_MAX_PREFER);
+		if (!ini->max_links)
+			return SMC_CLC_DECL_MAXLINKERR;
 	}
 
 	return 0;
@@ -1208,6 +1216,10 @@ int smc_clc_cli_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
 		if (fce_v2x->max_conns > SMC_CONN_PER_LGR_MAX)
 			return SMC_CLC_DECL_MAXCONNERR;
 		ini->max_conns = fce_v2x->max_conns;
+
+		if (fce_v2x->max_links > SMC_LINKS_ADD_LNK_MAX)
+			return SMC_CLC_DECL_MAXLINKERR;
+		ini->max_links = fce_v2x->max_links;
 	}
 
 	return 0;
@@ -1236,6 +1248,8 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
 	if (!ini->is_smcd) {
 		if (fce_v2x->max_conns != ini->max_conns)
 			return SMC_CLC_DECL_MAXCONNERR;
+		if (fce_v2x->max_links != ini->max_links)
+			return SMC_CLC_DECL_MAXLINKERR;
 	}
 
 	return 0;
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 54077e50c368..53fb20d7c14d 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -47,6 +47,7 @@
 #define SMC_CLC_DECL_NOUEID	0x03030008  /* peer sent no UEID	      */
 #define SMC_CLC_DECL_RELEASEERR	0x03030009  /* release version negotiate failed */
 #define SMC_CLC_DECL_MAXCONNERR	0x0303000a  /* max connections negotiate failed */
+#define SMC_CLC_DECL_MAXLINKERR	0x0303000b  /* max links negotiate failed */
 #define SMC_CLC_DECL_MODEUNSUPP	0x03040000  /* smc modes do not match (R or D)*/
 #define SMC_CLC_DECL_RMBE_EC	0x03050000  /* peer has eyecatcher in RMBE    */
 #define SMC_CLC_DECL_OPTUNSUPP	0x03060000  /* fastopen sockopt not supported */
@@ -136,7 +137,8 @@ struct smc_clc_v2_extension {
 	struct smc_clnt_opts_area_hdr hdr;
 	u8 roce[16];		/* RoCEv2 GID */
 	u8 max_conns;
-	u8 reserved[15];
+	u8 max_links;
+	u8 reserved[14];
 	u8 user_eids[][SMC_MAX_EID_LEN];
 };
 
@@ -239,7 +241,8 @@ struct smc_clc_first_contact_ext {
 struct smc_clc_first_contact_ext_v2x {
 	struct smc_clc_first_contact_ext fce_v20;
 	u8 max_conns; /* for SMC-R only */
-	u8 reserved3[3];
+	u8 max_links; /* for SMC-R only */
+	u8 reserved3[2];
 	__be32 vendor_exp_options;
 	u8 reserved4[8];
 } __packed;		/* format defined in
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 5de1fbaa6e28..d5967826bcdf 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -896,10 +896,12 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
 			memcpy(lgr->nexthop_mac, ini->smcrv2.nexthop_mac,
 			       ETH_ALEN);
 			lgr->max_conns = ini->max_conns;
+			lgr->max_links = ini->max_links;
 		} else {
 			ibdev = ini->ib_dev;
 			ibport = ini->ib_port;
 			lgr->max_conns = SMC_RMBS_PER_LGR_MAX;
+			lgr->max_links = SMC_LINKS_ADD_LNK_MAX;
 		}
 		memcpy(lgr->pnet_id, ibdev->pnetid[ibport - 1],
 		       SMC_MAX_PNETID_LEN);
@@ -1667,6 +1669,9 @@ void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport)
 		    !rdma_dev_access_netns(smcibdev->ibdev, lgr->net))
 			continue;
 
+		if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+			continue;
+
 		/* trigger local add link processing */
 		link = smc_llc_usable_link(lgr);
 		if (link)
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 065369dc6584..60820b71c1c7 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -165,6 +165,8 @@ struct smc_link {
  */
 #define SMC_LINKS_PER_LGR_MAX	3
 #define SMC_SINGLE_LINK		0
+#define SMC_LINKS_PER_LGR_MAX_PREFER	2	/* prefer 2 links max per lgr */
+#define SMC_LINKS_ADD_LNK_MAX	2
 
 /* tx/rx buffer list element for sndbufs list and rmbs list of a lgr */
 struct smc_buf_desc {
@@ -334,6 +336,8 @@ struct smc_link_group {
 			struct net		*net;
 			u8			max_conns;
 						/* max conn can be assigned to lgr */
+			u8			max_links;
+						/* max links can be added in lgr */
 		};
 		struct { /* SMC-D */
 			u64			peer_gid;
@@ -379,6 +383,7 @@ struct smc_init_info {
 	u8			smc_type_v2;
 	u8			release_ver;
 	u8			max_conns;
+	u8			max_links;
 	u8			first_contact_peer;
 	u8			first_contact_local;
 	unsigned short		vlan_id;
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 5347b62f1518..41e5e149edf3 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -59,8 +59,6 @@ struct smc_llc_msg_confirm_link {	/* type 0x01 */
 #define SMC_LLC_FLAG_ADD_LNK_REJ	0x40
 #define SMC_LLC_REJ_RSN_NO_ALT_PATH	1
 
-#define SMC_LLC_ADD_LNK_MAX_LINKS	2
-
 struct smc_llc_msg_add_link {		/* type 0x02 */
 	struct smc_llc_hdr hd;
 	u8 sender_mac[ETH_ALEN];
@@ -472,10 +470,12 @@ int smc_llc_send_confirm_link(struct smc_link *link,
 	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
 	confllc->link_num = link->link_id;
 	memcpy(confllc->link_uid, link->link_uid, SMC_LGR_ID_SIZE);
-	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
+	confllc->max_links = SMC_LINKS_ADD_LNK_MAX;
 	if (link->lgr->smc_version == SMC_V2 &&
-	    link->lgr->peer_smc_release >= SMC_RELEASE_1)
+	    link->lgr->peer_smc_release >= SMC_RELEASE_1) {
 		confllc->max_conns = link->lgr->max_conns;
+		confllc->max_links = link->lgr->max_links;
+	}
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
 put_out:
@@ -1045,6 +1045,9 @@ int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
 		goto out_reject;
 	}
 
+	if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+		goto out_reject;
+
 	ini->vlan_id = lgr->vlan_id;
 	if (lgr->smc_version == SMC_V2) {
 		ini->check_smcrv2 = true;
@@ -1169,6 +1172,9 @@ static void smc_llc_cli_add_link_invite(struct smc_link *link,
 	    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
 		goto out;
 
+	if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+		goto out;
+
 	ini = kzalloc(sizeof(*ini), GFP_KERNEL);
 	if (!ini)
 		goto out;
@@ -1414,6 +1420,9 @@ int smc_llc_srv_add_link(struct smc_link *link,
 		goto out;
 	}
 
+	if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+		goto out;
+
 	/* ignore client add link recommendation, start new flow */
 	ini->vlan_id = lgr->vlan_id;
 	if (lgr->smc_version == SMC_V2) {
-- 
2.24.3 (Apple Git-128)