smb: client: fix sending the iwrap custom IRD/ORD negotiation messages

Do a real negotiation and check the servers initiator_depth and
responder_resources.

This should use big endian in order to be useful.
I have captures of windows clients showing this.

The fact that we used little endian up to now
means that we sent very large numbers and the
negotiation with the server truncated them to the
server limits.

Note the reason why this uses u8 for
initiator_depth and responder_resources is
that the rdma layer also uses it.

The inconsitency regarding the initiator_depth
and responder_resources values being reversed
for iwarp devices in RDMA_CM_EVENT_ESTABLISHED
should also be fixed later, but for now we should
fix it.

Cc: Steve French <[email protected]>
Cc: Tom Talpey <[email protected]>
Cc: Long Li <[email protected]>
Acked-by: Namjae Jeon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Fixes: c739858 ("CIFS: SMBD: Implement RDMA memory registration")
Signed-off-by: Stefan Metzmacher <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: metze-samba

fs/smb/client/smbdirect.c

@@ -179,6 +179,8 @@ static int smbd_conn_upcall(
 	struct smbd_connection *info = id->context;
 	struct smbdirect_socket *sc = &info->socket;
 	const char *event_name = rdma_event_msg(event->event);
+	u8 peer_initiator_depth;
+	u8 peer_responder_resources;
 
 	log_rdma_event(INFO, "event=%s status=%d\n",
 		event_name, event->status);
@@ -204,6 +206,85 @@ static int smbd_conn_upcall(
 
 	case RDMA_CM_EVENT_ESTABLISHED:
 		log_rdma_event(INFO, "connected event=%s\n", event_name);
+
+		/*
+		 * Here we work around an inconsistency between
+		 * iWarp and other devices (at least rxe and irdma using RoCEv2)
+		 */
+		if (rdma_protocol_iwarp(id->device, id->port_num)) {
+			/*
+			 * iWarp devices report the peer's values
+			 * with the perspective of the peer here.
+			 * Tested with siw and irdma (in iwarp mode)
+			 * We need to change to our perspective here,
+			 * so we need to switch the values.
+			 */
+			peer_initiator_depth = event->param.conn.responder_resources;
+			peer_responder_resources = event->param.conn.initiator_depth;
+		} else {
+			/*
+			 * Non iWarp devices report the peer's values
+			 * already changed to our perspective here.
+			 * Tested with rxe and irdma (in roce mode).
+			 */
+			peer_initiator_depth = event->param.conn.initiator_depth;
+			peer_responder_resources = event->param.conn.responder_resources;
+		}
+		if (rdma_protocol_iwarp(id->device, id->port_num) &&
+		    event->param.conn.private_data_len == 8) {
+			/*
+			 * Legacy clients with only iWarp MPA v1 support
+			 * need a private blob in order to negotiate
+			 * the IRD/ORD values.
+			 */
+			const __be32 *ird_ord_hdr = event->param.conn.private_data;
+			u32 ird32 = be32_to_cpu(ird_ord_hdr[0]);
+			u32 ord32 = be32_to_cpu(ird_ord_hdr[1]);
+
+			/*
+			 * cifs.ko sends the legacy IRD/ORD negotiation
+			 * event if iWarp MPA v2 was used.
+			 *
+			 * Here we check that the values match and only
+			 * mark the client as legacy if they don't match.
+			 */
+			if ((u32)event->param.conn.initiator_depth != ird32 ||
+			    (u32)event->param.conn.responder_resources != ord32) {
+				/*
+				 * There are broken clients (old cifs.ko)
+				 * using little endian and also
+				 * struct rdma_conn_param only uses u8
+				 * for initiator_depth and responder_resources,
+				 * so we truncate the value to U8_MAX.
+				 *
+				 * smb_direct_accept_client() will then
+				 * do the real negotiation in order to
+				 * select the minimum between client and
+				 * server.
+				 */
+				ird32 = min_t(u32, ird32, U8_MAX);
+				ord32 = min_t(u32, ord32, U8_MAX);
+
+				info->legacy_iwarp = true;
+				peer_initiator_depth = (u8)ird32;
+				peer_responder_resources = (u8)ord32;
+			}
+		}
+
+		/*
+		 * negotiate the value by using the minimum
+		 * between client and server if the client provided
+		 * non 0 values.
+		 */
+		if (peer_initiator_depth != 0)
+			info->initiator_depth =
+					min_t(u8, info->initiator_depth,
+					      peer_initiator_depth);
+		if (peer_responder_resources != 0)
+			info->responder_resources =
+					min_t(u8, info->responder_resources,
+					      peer_responder_resources);
+
 		sc->status = SMBDIRECT_SOCKET_CONNECTED;
 		wake_up_interruptible(&info->status_wait);
 		break;
@@ -1551,14 +1632,17 @@ static struct smbd_connection *_smbd_get_connection(
 	struct ib_qp_init_attr qp_attr;
 	struct sockaddr_in *addr_in = (struct sockaddr_in *) dstaddr;
 	struct ib_port_immutable port_immutable;
-	u32 ird_ord_hdr[2];
+	__be32 ird_ord_hdr[2];
 
 	info = kzalloc(sizeof(struct smbd_connection), GFP_KERNEL);
 	if (!info)
 		return NULL;
 	sc = &info->socket;
 	sp = &sc->parameters;
 
+	info->initiator_depth = 1;
+	info->responder_resources = SMBD_CM_RESPONDER_RESOURCES;
+
 	sc->status = SMBDIRECT_SOCKET_CONNECTING;
 	rc = smbd_ia_open(info, dstaddr, port);
 	if (rc) {
@@ -1639,22 +1723,22 @@ static struct smbd_connection *_smbd_get_connection(
 	}
 	sc->ib.qp = sc->rdma.cm_id->qp;
 
-	memset(&conn_param, 0, sizeof(conn_param));
-	conn_param.initiator_depth = 0;
-
-	conn_param.responder_resources =
-		min(sc->ib.dev->attrs.max_qp_rd_atom,
-		    SMBD_CM_RESPONDER_RESOURCES);
-	info->responder_resources = conn_param.responder_resources;
+	info->responder_resources =
+		min_t(u8, info->responder_resources,
+		      sc->ib.dev->attrs.max_qp_rd_atom);
 	log_rdma_mr(INFO, "responder_resources=%d\n",
 		info->responder_resources);
 
+	memset(&conn_param, 0, sizeof(conn_param));
+	conn_param.initiator_depth = info->initiator_depth;
+	conn_param.responder_resources = info->responder_resources;
+
 	/* Need to send IRD/ORD in private data for iWARP */
 	sc->ib.dev->ops.get_port_immutable(
 		sc->ib.dev, sc->rdma.cm_id->port_num, &port_immutable);
 	if (port_immutable.core_cap_flags & RDMA_CORE_PORT_IWARP) {
-		ird_ord_hdr[0] = info->responder_resources;
-		ird_ord_hdr[1] = 1;
+		ird_ord_hdr[0] = cpu_to_be32(conn_param.responder_resources);
+		ird_ord_hdr[1] = cpu_to_be32(conn_param.initiator_depth);
 		conn_param.private_data = ird_ord_hdr;
 		conn_param.private_data_len = sizeof(ird_ord_hdr);
 	} else {
@@ -2121,6 +2205,12 @@ static int allocate_mr_list(struct smbd_connection *info)
 	atomic_set(&info->mr_used_count, 0);
 	init_waitqueue_head(&info->wait_for_mr_cleanup);
 	INIT_WORK(&info->mr_recovery_work, smbd_mr_recovery_work);
+
+	if (info->responder_resources == 0) {
+		log_rdma_mr(ERR, "responder_resources negotiated as 0\n");
+		return -EINVAL;
+	}
+
 	/* Allocate more MRs (2x) than hardware responder_resources */
 	for (i = 0; i < info->responder_resources * 2; i++) {
 		smbdirect_mr = kzalloc(sizeof(*smbdirect_mr), GFP_KERNEL);

fs/smb/client/smbdirect.h

@@ -67,7 +67,9 @@ struct smbd_connection {
 
 	/* Memory registrations */
 	/* Maximum number of RDMA read/write outstanding on this connection */
-	int responder_resources;
+	bool legacy_iwarp;
+	u8 initiator_depth;
+	u8 responder_resources;
 	/* Maximum number of pages in a single RDMA write/read on this connection */
 	int max_frmr_depth;
 	/*