net/smc: support max connections per lgr negotiation

Support max connections per lgr negotiation for SMCR v2.1,
which is one of smc v2.1 features. Server makes decision for
the final value of max conns based on the client preferred
max conns and self-preferred max conns. Here use the minimum
value of client preferred max conns and server preferred max
conns.

Client                                     Server
     Proposal(max conns(client preferred))
     ------------------------------------>

     Accept(max conns(accepted value))
accepted value=min(client preferred, server preferred)
     <-----------------------------------

     Confirm(max conns(accepted value))
     ----------------------------------->

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>

1 files changed, 36 insertions, 2 deletions

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 0232f189dad9..c88f5e2e65a2 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -427,9 +427,17 @@ static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
 	fce->fce_v2_base.os_type = SMC_CLC_OS_LINUX;
 	fce->fce_v2_base.release = ini->release_nr;
 	memcpy(fce->fce_v2_base.hostname, smc_hostname, sizeof(smc_hostname));
-	if (ini->is_smcd && ini->release_nr < SMC_RELEASE_1)
+	if (ini->is_smcd && ini->release_nr < SMC_RELEASE_1) {
 		ret = sizeof(struct smc_clc_first_contact_ext);
+		goto out;
+	}
+
+	if (ini->release_nr >= SMC_RELEASE_1) {
+		if (!ini->is_smcd)
+			fce->max_conns = ini->max_conns;
+	}
 
+out:
 	return ret;
 }
 
@@ -931,8 +939,10 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 				sizeof(struct smc_clc_smcd_gid_chid);
 		}
 	}
-	if (smcr_indicated(ini->smc_type_v2))
+	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_PREFER;
+	}
 
 	pclc_base->hdr.length = htons(plen);
 	memcpy(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
@@ -1163,6 +1173,8 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
 {
 	struct smc_clc_v2_extension *pclc_v2_ext;
 
+	ini->max_conns = SMC_CONN_PER_LGR_MAX;
+
 	if ((!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) ||
 	    ini->release_nr < SMC_RELEASE_1)
 		return 0;
@@ -1171,15 +1183,30 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
 	if (!pclc_v2_ext)
 		return SMC_CLC_DECL_NOV2EXT;
 
+	if (ini->smcr_version & SMC_V2) {
+		ini->max_conns = min_t(u8, pclc_v2_ext->max_conns, SMC_CONN_PER_LGR_PREFER);
+		if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
+			return SMC_CLC_DECL_MAXCONNERR;
+	}
+
 	return 0;
 }
 
 int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
 				       struct smc_init_info *ini)
 {
+	struct smc_clc_first_contact_ext_v2x *fce_v2x =
+		(struct smc_clc_first_contact_ext_v2x *)fce;
+
 	if (ini->release_nr < SMC_RELEASE_1)
 		return 0;
 
+	if (!ini->is_smcd) {
+		if (fce_v2x->max_conns < SMC_CONN_PER_LGR_MIN)
+			return SMC_CLC_DECL_MAXCONNERR;
+		ini->max_conns = fce_v2x->max_conns;
+	}
+
 	return 0;
 }
 
@@ -1190,6 +1217,8 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
 		(struct smc_clc_msg_accept_confirm_v2 *)cclc;
 	struct smc_clc_first_contact_ext *fce =
 		smc_get_clc_first_contact_ext(clc_v2, ini->is_smcd);
+	struct smc_clc_first_contact_ext_v2x *fce_v2x =
+		(struct smc_clc_first_contact_ext_v2x *)fce;
 
 	if (cclc->hdr.version == SMC_V1 ||
 	    !(cclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
@@ -1201,6 +1230,11 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
 	if (fce->release < SMC_RELEASE_1)
 		return 0;
 
+	if (!ini->is_smcd) {
+		if (fce_v2x->max_conns != ini->max_conns)
+			return SMC_CLC_DECL_MAXCONNERR;
+	}
+
 	return 0;
 }