net/smc: create improved SMC-R link_uid

The link_uid of an SMC-R link is exchanged between SMC peers and its
value can be used for debugging purposes. Create a unique link_uid
during link initialization and use it in communication with SMC-R peers.
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_core.c

@@ -331,6 +331,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 	lnk->smcibdev = ini->ib_dev;
 	lnk->ibport = ini->ib_port;
 	lnk->path_mtu = ini->ib_dev->pattr[ini->ib_port - 1].active_mtu;
+	smc_llc_link_set_uid(lnk);
 	INIT_WORK(&lnk->link_down_wrk, smc_link_down_work);
 	if (!ini->ib_dev->initialized) {
 		rc = (int)smc_ib_setup_per_ibdev(ini->ib_dev);

net/smc/smc_core.h

@@ -70,6 +70,8 @@ struct smc_rdma_wr {				/* work requests per message
 	struct ib_rdma_wr	wr_tx_rdma[SMC_MAX_RDMA_WRITES];
 };
 
+#define SMC_LGR_ID_SIZE		4
+
 struct smc_link {
 	struct smc_ib_device	*smcibdev;	/* ib-device */
 	u8			ibport;		/* port - values 1 | 2 */
@@ -116,6 +118,7 @@ struct smc_link {
 	u8			peer_mac[ETH_ALEN];	/* = gid[8:10||13:15] */
 	u8			peer_gid[SMC_GID_SIZE];	/* gid of peer*/
 	u8			link_id;	/* unique # within link group */
+	u8			link_uid[SMC_LGR_ID_SIZE]; /* unique lnk id */
 	u8			link_idx;	/* index in lgr link array */
 	u8			link_is_asym;	/* is link asymmetric? */
 	struct smc_link_group	*lgr;		/* parent link group */
@@ -178,7 +181,6 @@ struct smc_rtoken {				/* address/key of remote RMB */
 	u32			rkey;
 };
 
-#define SMC_LGR_ID_SIZE		4
 #define SMC_BUF_MIN_SIZE	16384	/* minimum size of an RMB */
 #define SMC_RMBE_SIZES		16	/* number of distinct RMBE sizes */
 /* theoretically, the RFC states that largest size would be 512K,

net/smc/smc_llc.c

@@ -361,7 +361,6 @@ static int smc_llc_add_pending_send(struct smc_link *link,
 int smc_llc_send_confirm_link(struct smc_link *link,
 			      enum smc_llc_reqresp reqresp)
 {
-	struct smc_link_group *lgr = smc_get_lgr(link);
 	struct smc_llc_msg_confirm_link *confllc;
 	struct smc_wr_tx_pend_priv *pend;
 	struct smc_wr_buf *wr_buf;
@@ -382,7 +381,7 @@ int smc_llc_send_confirm_link(struct smc_link *link,
 	memcpy(confllc->sender_gid, link->gid, SMC_GID_SIZE);
 	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
 	confllc->link_num = link->link_id;
-	memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
+	memcpy(confllc->link_uid, link->link_uid, SMC_LGR_ID_SIZE);
 	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
@@ -845,7 +844,8 @@ int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
 	if (rc)
 		goto out_reject;
 	smc_llc_save_add_link_info(lnk_new, llc);
-	lnk_new->link_id = llc->link_num;
+	lnk_new->link_id = llc->link_num;	/* SMC server assigns link id */
+	smc_llc_link_set_uid(lnk_new);
 
 	rc = smc_ib_ready_link(lnk_new);
 	if (rc)
@@ -1775,12 +1775,22 @@ int smc_llc_do_delete_rkey(struct smc_link_group *lgr,
 	return rc;
 }
 
+void smc_llc_link_set_uid(struct smc_link *link)
+{
+	__be32 link_uid;
+
+	link_uid = htonl(*((u32 *)link->lgr->id) + link->link_id);
+	memcpy(link->link_uid, &link_uid, SMC_LGR_ID_SIZE);
+}
+
 /* evaluate confirm link request or response */
 int smc_llc_eval_conf_link(struct smc_llc_qentry *qentry,
 			   enum smc_llc_reqresp type)
 {
-	if (type == SMC_LLC_REQ)	/* SMC server assigns link_id */
+	if (type == SMC_LLC_REQ) {	/* SMC server assigns link_id */
 		qentry->link->link_id = qentry->msg.confirm_link.link_num;
+		smc_llc_link_set_uid(qentry->link);
+	}
 	if (!(qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
 		return -ENOTSUPP;
 	return 0;

net/smc/smc_llc.h

@@ -92,6 +92,7 @@ int smc_llc_flow_initiate(struct smc_link_group *lgr,
 void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow);
 int smc_llc_eval_conf_link(struct smc_llc_qentry *qentry,
 			   enum smc_llc_reqresp type);
+void smc_llc_link_set_uid(struct smc_link *link);
 struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
 				    struct smc_link *lnk,
 				    int time_out, u8 exp_msg);