net/smc: support smc release version negotiation in clc handshake

Support smc release version negotiation in clc handshake based on
SMC v2, where no negotiation process for different releases, but
for different versions. The latest smc release version was updated
to v2.1. And currently there are two release versions of SMCv2, v2.0
and v2.1. In the release version negotiation, client sends the preferred
release version by CLC Proposal Message, server makes decision for which
release version to use based on the client preferred release version and
self-supported release version (here choose the minimum release version
of the client preferred and server latest supported), then the decision
returns to client by CLC Accept Message. Client confirms the decision by
CLC Confirm Message.

Client                                    Server
      Proposal(preferred release version)
     ------------------------------------>

      Accept(accpeted release version)
 min(client preferred, server latest supported)
     <------------------------------------

      Confirm(accpeted release version)
     ------------------------------------>

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: GuangguanWang

net/smc/af_smc.c

@@ -1198,8 +1198,7 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
 	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
 		(struct smc_clc_msg_accept_confirm_v2 *)aclc;
 	struct smc_clc_first_contact_ext *fce =
-		(struct smc_clc_first_contact_ext *)
-			(((u8 *)clc_v2) + sizeof(*clc_v2));
+		smc_get_clc_first_contact_ext(clc_v2, false);
 
 	if (!ini->first_contact_peer || aclc->hdr.version == SMC_V1)
 		return 0;
@@ -1218,6 +1217,9 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
 			return SMC_CLC_DECL_NOINDIRECT;
 		}
 	}
+
+	ini->release_nr = fce->release;
+
 	return 0;
 }
 
@@ -1386,6 +1388,13 @@ static int smc_connect_ism(struct smc_sock *smc,
 		struct smc_clc_msg_accept_confirm_v2 *aclc_v2 =
 			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
 
+		if (ini->first_contact_peer) {
+			struct smc_clc_first_contact_ext *fce =
+				smc_get_clc_first_contact_ext(aclc_v2, true);
+
+			ini->release_nr = fce->release;
+		}
+
 		rc = smc_v2_determine_accepted_chid(aclc_v2, ini);
 		if (rc)
 			return rc;
@@ -1420,7 +1429,7 @@ static int smc_connect_ism(struct smc_sock *smc,
 	}
 
 	rc = smc_clc_send_confirm(smc, ini->first_contact_local,
-				  aclc->hdr.version, eid, NULL);
+				  aclc->hdr.version, eid, ini);
 	if (rc)
 		goto connect_abort;
 	mutex_unlock(&smc_server_lgr_pending);
@@ -1996,6 +2005,10 @@ static int smc_listen_v2_check(struct smc_sock *new_smc,
 		}
 	}
 
+	ini->release_nr = pclc_v2_ext->hdr.flag.release;
+	if (pclc_v2_ext->hdr.flag.release > SMC_RELEASE)
+		ini->release_nr = SMC_RELEASE;
+
 out:
 	if (!ini->smcd_version && !ini->smcr_version)
 		return rc;
@@ -2443,7 +2456,7 @@ static void smc_listen_work(struct work_struct *work)
 	/* send SMC Accept CLC message */
 	accept_version = ini->is_smcd ? ini->smcd_version : ini->smcr_version;
 	rc = smc_clc_send_accept(new_smc, ini->first_contact_local,
-				 accept_version, ini->negotiated_eid);
+				 accept_version, ini->negotiated_eid, ini);
 	if (rc)
 		goto out_unlock;
 

net/smc/smc.h

@@ -21,7 +21,10 @@
 
 #define SMC_V1		1		/* SMC version V1 */
 #define SMC_V2		2		/* SMC version V2 */
-#define SMC_RELEASE	0
+
+#define SMC_RELEASE_0 0
+#define SMC_RELEASE_1 1
+#define SMC_RELEASE	SMC_RELEASE_1 /* the latest release version */
 
 #define SMCPROTO_SMC		0	/* SMC protocol, IPv4 */
 #define SMCPROTO_SMC6		1	/* SMC protocol, IPv6 */

net/smc/smc_clc.c

@@ -420,11 +420,11 @@ smc_clc_msg_decl_valid(struct smc_clc_msg_decline *dclc)
 	return true;
 }
 
-static void smc_clc_fill_fce(struct smc_clc_first_contact_ext *fce, int *len)
+static void smc_clc_fill_fce(struct smc_clc_first_contact_ext *fce, int *len, int release_nr)
 {
 	memset(fce, 0, sizeof(*fce));
 	fce->os_type = SMC_CLC_OS_LINUX;
-	fce->release = SMC_RELEASE;
+	fce->release = release_nr;
 	memcpy(fce->hostname, smc_hostname, sizeof(smc_hostname));
 	(*len) += sizeof(*fce);
 }
@@ -1019,7 +1019,7 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 				memcpy(clc_v2->d1.eid, eid, SMC_MAX_EID_LEN);
 			len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2;
 			if (first_contact)
-				smc_clc_fill_fce(&fce, &len);
+				smc_clc_fill_fce(&fce, &len, ini->release_nr);
 			clc_v2->hdr.length = htons(len);
 		}
 		memcpy(trl.eyecatcher, SMCD_EYECATCHER,
@@ -1063,10 +1063,10 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 				memcpy(clc_v2->r1.eid, eid, SMC_MAX_EID_LEN);
 			len = SMCR_CLC_ACCEPT_CONFIRM_LEN_V2;
 			if (first_contact) {
-				smc_clc_fill_fce(&fce, &len);
+				smc_clc_fill_fce(&fce, &len, ini->release_nr);
 				fce.v2_direct = !link->lgr->uses_gateway;
 				memset(&gle, 0, sizeof(gle));
-				if (ini && clc->hdr.type == SMC_CLC_CONFIRM) {
+				if (clc->hdr.type == SMC_CLC_CONFIRM) {
 					gle.gid_cnt = ini->smcrv2.gidlist.len;
 					len += sizeof(gle);
 					len += gle.gid_cnt * sizeof(gle.gid[0]);
@@ -1141,15 +1141,15 @@ int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
 
 /* send CLC ACCEPT message across internal TCP socket */
 int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
-			u8 version, u8 *negotiated_eid)
+			u8 version, u8 *negotiated_eid, struct smc_init_info *ini)
 {
 	struct smc_clc_msg_accept_confirm_v2 aclc_v2;
 	int len;
 
 	memset(&aclc_v2, 0, sizeof(aclc_v2));
 	aclc_v2.hdr.type = SMC_CLC_ACCEPT;
 	len = smc_clc_send_confirm_accept(new_smc, &aclc_v2, srv_first_contact,
-					  version, negotiated_eid, NULL);
+					  version, negotiated_eid, ini);
 	if (len < ntohs(aclc_v2.hdr.length))
 		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;
 

net/smc/smc_clc.h

@@ -370,6 +370,27 @@ smc_get_clc_smcd_v2_ext(struct smc_clc_v2_extension *prop_v2ext)
 		 ntohs(prop_v2ext->hdr.smcd_v2_ext_offset));
 }
 
+static inline struct smc_clc_first_contact_ext *
+smc_get_clc_first_contact_ext(struct smc_clc_msg_accept_confirm_v2 *clc_v2,
+			      bool is_smcd)
+{
+	int clc_v2_len;
+
+	if (clc_v2->hdr.version == SMC_V1 ||
+	    !(clc_v2->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
+		return NULL;
+
+	if (is_smcd)
+		clc_v2_len =
+			offsetofend(struct smc_clc_msg_accept_confirm_v2, d1);
+	else
+		clc_v2_len =
+			offsetofend(struct smc_clc_msg_accept_confirm_v2, r1);
+
+	return (struct smc_clc_first_contact_ext *)(((u8 *)clc_v2) +
+						    clc_v2_len);
+}
+
 struct smcd_dev;
 struct smc_init_info;
 
@@ -382,7 +403,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini);
 int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
 			 u8 version, u8 *eid, struct smc_init_info *ini);
 int smc_clc_send_accept(struct smc_sock *smc, bool srv_first_contact,
-			u8 version, u8 *negotiated_eid);
+			u8 version, u8 *negotiated_eid, struct smc_init_info *ini);
 void smc_clc_init(void) __init;
 void smc_clc_exit(void);
 void smc_clc_get_hostname(u8 **host);

net/smc/smc_core.h

@@ -374,6 +374,7 @@ struct smc_init_info {
 	u8			is_smcd;
 	u8			smc_type_v1;
 	u8			smc_type_v2;
+	u8			release_nr;
 	u8			first_contact_peer;
 	u8			first_contact_local;
 	unsigned short		vlan_id;