net/smc: process add/delete link messages

Add initial support for the LLC messages ADD LINK and DELETE LINK.
Introduce a link state field. Extend the initial LLC handshake with
ADD LINK processing.
Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -313,6 +313,27 @@ static int smc_clnt_conf_first_link(struct smc_sock *smc)
 	if (rc < 0)
 		return SMC_CLC_DECL_TCL;
 
+	/* receive ADD LINK request from server over RoCE fabric */
+	rest = wait_for_completion_interruptible_timeout(&link->llc_add,
+							 SMC_LLC_WAIT_TIME);
+	if (rest <= 0) {
+		struct smc_clc_msg_decline dclc;
+
+		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+				      SMC_CLC_DECLINE);
+		return rc;
+	}
+
+	/* send add link reject message, only one link supported for now */
+	rc = smc_llc_send_add_link(link,
+				   link->smcibdev->mac[link->ibport - 1],
+				   &link->smcibdev->gid[link->ibport - 1],
+				   SMC_LLC_RESP);
+	if (rc < 0)
+		return SMC_CLC_DECL_TCL;
+
+	link->state = SMC_LNK_ACTIVE;
+
 	return 0;
 }
 
@@ -714,6 +735,27 @@ static int smc_serv_conf_first_link(struct smc_sock *smc)
 	if (link->llc_confirm_resp_rc)
 		return SMC_CLC_DECL_RMBE_EC;
 
+	/* send ADD LINK request to client over the RoCE fabric */
+	rc = smc_llc_send_add_link(link,
+				   link->smcibdev->mac[link->ibport - 1],
+				   &link->smcibdev->gid[link->ibport - 1],
+				   SMC_LLC_REQ);
+	if (rc < 0)
+		return SMC_CLC_DECL_TCL;
+
+	/* receive ADD LINK response from client over the RoCE fabric */
+	rest = wait_for_completion_interruptible_timeout(&link->llc_add_resp,
+							 SMC_LLC_WAIT_TIME);
+	if (rest <= 0) {
+		struct smc_clc_msg_decline dclc;
+
+		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+				      SMC_CLC_DECLINE);
+		return rc;
+	}
+
+	link->state = SMC_LNK_ACTIVE;
+
 	return 0;
 }
 

net/smc/smc_core.c

@@ -176,6 +176,7 @@ static int smc_lgr_create(struct smc_sock *smc,
 
 	lnk = &lgr->lnk[SMC_SINGLE_LINK];
 	/* initialize link */
+	lnk->state = SMC_LNK_ACTIVATING;
 	lnk->smcibdev = smcibdev;
 	lnk->ibport = ibport;
 	lnk->path_mtu = smcibdev->pattr[ibport - 1].active_mtu;
@@ -197,6 +198,8 @@ static int smc_lgr_create(struct smc_sock *smc,
 		goto destroy_qp;
 	init_completion(&lnk->llc_confirm);
 	init_completion(&lnk->llc_confirm_resp);
+	init_completion(&lnk->llc_add);
+	init_completion(&lnk->llc_add_resp);
 
 	smc->conn.lgr = lgr;
 	rwlock_init(&lgr->conns_lock);

net/smc/smc_core.h

@@ -32,6 +32,12 @@ enum smc_lgr_role {		/* possible roles of a link group */
 	SMC_SERV	/* server */
 };
 
+enum smc_link_state {			/* possible states of a link */
+	SMC_LNK_INACTIVE,	/* link is inactive */
+	SMC_LNK_ACTIVATING,	/* link is being activated */
+	SMC_LNK_ACTIVE		/* link is active */
+};
+
 #define SMC_WR_BUF_SIZE		48	/* size of work request buffer */
 
 struct smc_wr_buf {
@@ -87,10 +93,14 @@ struct smc_link {
 	u8			peer_mac[ETH_ALEN];	/* = gid[8:10||13:15] */
 	u8			peer_gid[sizeof(union ib_gid)];	/* gid of peer*/
 	u8			link_id;	/* unique # within link group */
+
+	enum smc_link_state	state;		/* state of link */
 	struct completion	llc_confirm;	/* wait for rx of conf link */
 	struct completion	llc_confirm_resp; /* wait 4 rx of cnf lnk rsp */
 	int			llc_confirm_rc; /* rc from confirm link msg */
 	int			llc_confirm_resp_rc; /* rc from conf_resp msg */
+	struct completion	llc_add;	/* wait for rx of add link */
+	struct completion	llc_add_resp;	/* wait for rx of add link rsp*/
 };
 
 /* For now we just allow one parallel link per link group. The SMC protocol

net/smc/smc_llc.c

@@ -4,9 +4,6 @@
  *
  *  Link Layer Control (LLC)
  *
- *  For now, we only support the necessary "confirm link" functionality
- *  which happens for the first RoCE link after successful CLC handshake.
- *
  *  Copyright IBM Corp. 2016
  *
  *  Author(s):  Klaus Wacker <Klaus.Wacker@de.ibm.com>
@@ -26,7 +23,13 @@
 struct smc_llc_hdr {
 	struct smc_wr_rx_hdr common;
 	u8 length;	/* 44 */
-	u8 reserved;
+#if defined(__BIG_ENDIAN_BITFIELD)
+	u8 reserved:4,
+	   add_link_rej_rsn:4;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+	u8 add_link_rej_rsn:4,
+	   reserved:4;
+#endif
 	u8 flags;
 };
 
@@ -43,6 +46,33 @@ struct smc_llc_msg_confirm_link {	/* type 0x01 */
 	u8 reserved[9];
 };
 
+#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];
+	u8 reserved2[2];
+	u8 sender_gid[SMC_GID_SIZE];
+	u8 sender_qp_num[3];
+	u8 link_num;
+	u8 flags2;	/* QP mtu */
+	u8 initial_psn[3];
+	u8 reserved[8];
+};
+
+#define SMC_LLC_FLAG_DEL_LINK_ALL	0x40
+#define SMC_LLC_FLAG_DEL_LINK_ORDERLY	0x20
+
+struct smc_llc_msg_del_link {		/* type 0x04 */
+	struct smc_llc_hdr hd;
+	u8 link_num;
+	__be32 reason;
+	u8 reserved[35];
+} __packed;			/* format defined in RFC7609 */
+
 struct smc_llc_msg_test_link {		/* type 0x07 */
 	struct smc_llc_hdr hd;
 	u8 user_data[16];
@@ -88,6 +118,8 @@ struct smc_llc_msg_delete_rkey {	/* type 0x09 */
 
 union smc_llc_msg {
 	struct smc_llc_msg_confirm_link confirm_link;
+	struct smc_llc_msg_add_link add_link;
+	struct smc_llc_msg_del_link delete_link;
 
 	struct smc_llc_msg_confirm_rkey confirm_rkey;
 	struct smc_llc_msg_confirm_rkey_cont confirm_rkey_cont;
@@ -176,7 +208,64 @@ int smc_llc_send_confirm_link(struct smc_link *link, u8 mac[],
 	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
 	/* confllc->link_num = SMC_SINGLE_LINK; already done by memset above */
 	memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
-	confllc->max_links = SMC_LINKS_PER_LGR_MAX;
+	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS; /* enforce peer resp. */
+	/* send llc message */
+	rc = smc_wr_tx_send(link, pend);
+	return rc;
+}
+
+/* send ADD LINK request or response */
+int smc_llc_send_add_link(struct smc_link *link, u8 mac[],
+			  union ib_gid *gid,
+			  enum smc_llc_reqresp reqresp)
+{
+	struct smc_llc_msg_add_link *addllc;
+	struct smc_wr_tx_pend_priv *pend;
+	struct smc_wr_buf *wr_buf;
+	int rc;
+
+	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
+	if (rc)
+		return rc;
+	addllc = (struct smc_llc_msg_add_link *)wr_buf;
+	memset(addllc, 0, sizeof(*addllc));
+	addllc->hd.common.type = SMC_LLC_ADD_LINK;
+	addllc->hd.length = sizeof(struct smc_llc_msg_add_link);
+	if (reqresp == SMC_LLC_RESP) {
+		addllc->hd.flags |= SMC_LLC_FLAG_RESP;
+		/* always reject more links for now */
+		addllc->hd.flags |= SMC_LLC_FLAG_ADD_LNK_REJ;
+		addllc->hd.add_link_rej_rsn = SMC_LLC_REJ_RSN_NO_ALT_PATH;
+	}
+	memcpy(addllc->sender_mac, mac, ETH_ALEN);
+	memcpy(addllc->sender_gid, gid, SMC_GID_SIZE);
+	/* send llc message */
+	rc = smc_wr_tx_send(link, pend);
+	return rc;
+}
+
+/* send DELETE LINK request or response */
+int smc_llc_send_delete_link(struct smc_link *link,
+			     enum smc_llc_reqresp reqresp)
+{
+	struct smc_llc_msg_del_link *delllc;
+	struct smc_wr_tx_pend_priv *pend;
+	struct smc_wr_buf *wr_buf;
+	int rc;
+
+	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
+	if (rc)
+		return rc;
+	delllc = (struct smc_llc_msg_del_link *)wr_buf;
+	memset(delllc, 0, sizeof(*delllc));
+	delllc->hd.common.type = SMC_LLC_DELETE_LINK;
+	delllc->hd.length = sizeof(struct smc_llc_msg_add_link);
+	if (reqresp == SMC_LLC_RESP)
+		delllc->hd.flags |= SMC_LLC_FLAG_RESP;
+	/* DEL_LINK_ALL because only 1 link supported */
+	delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
+	delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
+	delllc->link_num = link->link_id;
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
 	return rc;
@@ -239,12 +328,14 @@ static void smc_llc_rx_confirm_link(struct smc_link *link,
 		conf_rc = ENOTSUPP;
 
 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		if (lgr->role == SMC_SERV) {
+		if (lgr->role == SMC_SERV &&
+		    link->state == SMC_LNK_ACTIVATING) {
 			link->llc_confirm_resp_rc = conf_rc;
 			complete(&link->llc_confirm_resp);
 		}
 	} else {
-		if (lgr->role == SMC_CLNT) {
+		if (lgr->role == SMC_CLNT &&
+		    link->state == SMC_LNK_ACTIVATING) {
 			link->llc_confirm_rc = conf_rc;
 			link->link_id = llc->link_num;
 			complete(&link->llc_confirm);
@@ -252,6 +343,55 @@ static void smc_llc_rx_confirm_link(struct smc_link *link,
 	}
 }
 
+static void smc_llc_rx_add_link(struct smc_link *link,
+				struct smc_llc_msg_add_link *llc)
+{
+	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
+						  lnk[SMC_SINGLE_LINK]);
+
+	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
+		if (link->state == SMC_LNK_ACTIVATING)
+			complete(&link->llc_add_resp);
+	} else {
+		if (link->state == SMC_LNK_ACTIVATING) {
+			complete(&link->llc_add);
+			return;
+		}
+
+		if (lgr->role == SMC_SERV) {
+			smc_llc_send_add_link(link,
+					link->smcibdev->mac[link->ibport - 1],
+					&link->smcibdev->gid[link->ibport - 1],
+					SMC_LLC_REQ);
+
+		} else {
+			smc_llc_send_add_link(link,
+					link->smcibdev->mac[link->ibport - 1],
+					&link->smcibdev->gid[link->ibport - 1],
+					SMC_LLC_RESP);
+		}
+	}
+}
+
+static void smc_llc_rx_delete_link(struct smc_link *link,
+				   struct smc_llc_msg_del_link *llc)
+{
+	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
+						  lnk[SMC_SINGLE_LINK]);
+
+	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
+		if (lgr->role == SMC_SERV)
+			smc_lgr_terminate(lgr);
+	} else {
+		if (lgr->role == SMC_SERV) {
+			smc_llc_send_delete_link(link, SMC_LLC_REQ);
+		} else {
+			smc_llc_send_delete_link(link, SMC_LLC_RESP);
+			smc_lgr_terminate(lgr);
+		}
+	}
+}
+
 static void smc_llc_rx_test_link(struct smc_link *link,
 				 struct smc_llc_msg_test_link *llc)
 {
@@ -343,6 +483,12 @@ static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
 	case SMC_LLC_CONFIRM_LINK:
 		smc_llc_rx_confirm_link(link, &llc->confirm_link);
 		break;
+	case SMC_LLC_ADD_LINK:
+		smc_llc_rx_add_link(link, &llc->add_link);
+		break;
+	case SMC_LLC_DELETE_LINK:
+		smc_llc_rx_delete_link(link, &llc->delete_link);
+		break;
 	case SMC_LLC_CONFIRM_RKEY:
 		smc_llc_rx_confirm_rkey(link, &llc->confirm_rkey);
 		break;
@@ -366,6 +512,14 @@ static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
 		.handler	= smc_llc_rx_handler,
 		.type		= SMC_LLC_TEST_LINK
 	},
+	{
+		.handler	= smc_llc_rx_handler,
+		.type		= SMC_LLC_ADD_LINK
+	},
+	{
+		.handler	= smc_llc_rx_handler,
+		.type		= SMC_LLC_DELETE_LINK
+	},
 	{
 		.handler	= smc_llc_rx_handler,
 		.type		= SMC_LLC_CONFIRM_RKEY

net/smc/smc_llc.h

@@ -18,6 +18,7 @@
 #define SMC_LLC_FLAG_RESP		0x80
 
 #define SMC_LLC_WAIT_FIRST_TIME		(5 * HZ)
+#define SMC_LLC_WAIT_TIME		(2 * HZ)
 
 enum smc_llc_reqresp {
 	SMC_LLC_REQ,
@@ -26,6 +27,8 @@ enum smc_llc_reqresp {
 
 enum smc_llc_msg_type {
 	SMC_LLC_CONFIRM_LINK		= 0x01,
+	SMC_LLC_ADD_LINK		= 0x02,
+	SMC_LLC_DELETE_LINK		= 0x04,
 	SMC_LLC_CONFIRM_RKEY		= 0x06,
 	SMC_LLC_TEST_LINK		= 0x07,
 	SMC_LLC_CONFIRM_RKEY_CONT	= 0x08,
@@ -35,6 +38,10 @@ enum smc_llc_msg_type {
 /* transmit */
 int smc_llc_send_confirm_link(struct smc_link *lnk, u8 mac[], union ib_gid *gid,
 			      enum smc_llc_reqresp reqresp);
+int smc_llc_send_add_link(struct smc_link *link, u8 mac[], union ib_gid *gid,
+			  enum smc_llc_reqresp reqresp);
+int smc_llc_send_delete_link(struct smc_link *link,
+			     enum smc_llc_reqresp reqresp);
 int smc_llc_send_test_link(struct smc_link *lnk, u8 user_data[16],
 			   enum smc_llc_reqresp reqresp);
 int smc_llc_init(void) __init;