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Message-ID: <36db51b2-ff88-0419-1e9b-cae2b111e570@linux.ibm.com>
Date:   Wed, 16 Aug 2023 16:14:15 +0200
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Subject: Re: [PATCH net-next 1/6] net/smc: support smc release version
 negotiation in clc handshake
To:     Guangguan Wang <guangguan.wang@linux.alibaba.com>,
        wenjia@linux.ibm.com, kgraul@linux.ibm.com,
        tonylu@linux.alibaba.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com
Cc:     horms@kernel.org, alibuda@linux.alibaba.com,
        guwen@linux.alibaba.com, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230816083328.95746-1-guangguan.wang@linux.alibaba.com>
 <20230816083328.95746-2-guangguan.wang@linux.alibaba.com>
From:   Jan Karcher <jaka@linux.ibm.com>
Organization: IBM - Network Linux on Z
In-Reply-To: <20230816083328.95746-2-guangguan.wang@linux.alibaba.com>
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Precedence: bulk


On 16/08/2023 10:33, Guangguan Wang wrote:
> 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>
> ---
>   net/smc/af_smc.c   | 18 ++++++++++++++++--
>   net/smc/smc.h      |  5 ++++-
>   net/smc/smc_clc.c  | 14 +++++++-------
>   net/smc/smc_clc.h  | 23 ++++++++++++++++++++++-
>   net/smc/smc_core.h |  1 +
>   5 files changed, 50 insertions(+), 11 deletions(-)
> 
> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
> index a7f887d91d89..97265691bc95 100644
> --- a/net/smc/af_smc.c
> +++ b/net/smc/af_smc.c
> @@ -1187,6 +1187,9 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
>   			return SMC_CLC_DECL_NOINDIRECT;
>   		}
>   	}
> +
> +	ini->release_nr = fce->release;
> +

why would we do this and vvvvv
>   	return 0;
>   }
>   
> @@ -1355,6 +1358,13 @@ 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;
> +		}
> +

this two times?
Can't we put this together into __smc_connect where those functions get 
called (via smc_connect_rdma and smc_connect_ism)?

Please provide reasoning, it might be that i oversaw the reasoning 
behind this duplication.

Also note: Even if there is a reason to set this information seperate 
for SMC-D and SMC-R think about using your very neat helper function 
(smc_get_clc_first_contact_ext) in smc_connect_rdma_v2_prepare as well.

>   		rc = smc_v2_determine_accepted_chid(aclc_v2, ini);
>   		if (rc)
>   			return rc;
> @@ -1389,7 +1399,7 @@ 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);
> @@ -1965,6 +1975,10 @@ 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;
> @@ -2412,7 +2426,7 @@ 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;
>   
> diff --git a/net/smc/smc.h b/net/smc/smc.h
> index 2eeea4cdc718..9cce1a41e011 100644
> --- a/net/smc/smc.h
> +++ b/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 */
> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
> index b9b8b07aa702..7c5627c6abcc 100644
> --- a/net/smc/smc_clc.c
> +++ b/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]);
> @@ -1141,7 +1141,7 @@ 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;
> @@ -1149,7 +1149,7 @@ int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
>   	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;
>   
> diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
> index 5fee545c9a10..b923e89acafb 100644
> --- a/net/smc/smc_clc.h
> +++ b/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);
> diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
> index 3c1b31bfa1cf..b6c68db61f23 100644
> --- a/net/smc/smc_core.h
> +++ b/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;