[SCSI] iscsi: add sysfs attrs for uspace sync up

For iscsi boot when going from initramfs to the real root we
need to stop the userpsace iscsi daemon. To later restart it
iscsid needs to be able to rebuild itself and part of that
process is matching a session running the kernel with the
iscsid representation. To do this the attached patch
adds several required iscsi values. If the LLD does not provide
them becuase, login is done in userspace, then the transport
class and userspace set ths up for the LLD.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/iscsi_tcp.c

@@ -3536,7 +3536,7 @@ iscsi_session_get_param(struct iscsi_cls_session *cls_session,
 		*value = session->ofmarker_en;
 		break;
 	default:
-		return ISCSI_ERR_PARAM_NOT_FOUND;
+		return -EINVAL;
 	}
 
 	return 0;
@@ -3547,6 +3547,7 @@ iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
 		     enum iscsi_param param, uint32_t *value)
 {
 	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct inet_sock *inet;
 
 	switch(param) {
 	case ISCSI_PARAM_MAX_RECV_DLENGTH:
@@ -3561,13 +3562,61 @@ iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
 	case ISCSI_PARAM_DATADGST_EN:
 		*value = conn->datadgst_en;
 		break;
+	case ISCSI_PARAM_CONN_PORT:
+		mutex_lock(&conn->xmitmutex);
+		if (!conn->sock) {
+			mutex_unlock(&conn->xmitmutex);
+			return -EINVAL;
+		}
+
+		inet = inet_sk(conn->sock->sk);
+		*value = be16_to_cpu(inet->dport);
+		mutex_unlock(&conn->xmitmutex);
 	default:
-		return ISCSI_ERR_PARAM_NOT_FOUND;
+		return -EINVAL;
 	}
 
 	return 0;
 }
 
+static int
+iscsi_conn_get_str_param(struct iscsi_cls_conn *cls_conn,
+			 enum iscsi_param param, char *buf)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct sock *sk;
+	struct inet_sock *inet;
+	struct ipv6_pinfo *np;
+	int len = 0;
+
+	switch (param) {
+	case ISCSI_PARAM_CONN_ADDRESS:
+		mutex_lock(&conn->xmitmutex);
+		if (!conn->sock) {
+			mutex_unlock(&conn->xmitmutex);
+			return -EINVAL;
+		}
+
+		sk = conn->sock->sk;
+		if (sk->sk_family == PF_INET) {
+			inet = inet_sk(sk);
+			len = sprintf(buf, "%u.%u.%u.%u\n",
+				      NIPQUAD(inet->daddr));
+		} else {
+			np = inet6_sk(sk);
+			len = sprintf(buf,
+				"%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+				NIP6(np->daddr));
+		}
+		mutex_unlock(&conn->xmitmutex);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return len;
+}
+
 static void
 iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
 {
@@ -3610,6 +3659,20 @@ static struct iscsi_transport iscsi_tcp_transport = {
 	.name			= "tcp",
 	.caps			= CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
 				  | CAP_DATADGST,
+	.param_mask		= ISCSI_MAX_RECV_DLENGTH |
+				  ISCSI_MAX_XMIT_DLENGTH |
+				  ISCSI_HDRDGST_EN |
+				  ISCSI_DATADGST_EN |
+				  ISCSI_INITIAL_R2T_EN |
+				  ISCSI_MAX_R2T |
+				  ISCSI_IMM_DATA_EN |
+				  ISCSI_FIRST_BURST |
+				  ISCSI_MAX_BURST |
+				  ISCSI_PDU_INORDER_EN |
+				  ISCSI_DATASEQ_INORDER_EN |
+				  ISCSI_ERL |
+				  ISCSI_CONN_PORT |
+				  ISCSI_CONN_ADDRESS,
 	.host_template		= &iscsi_sht,
 	.hostdata_size		= sizeof(struct iscsi_session),
 	.conndata_size		= sizeof(struct iscsi_conn),
@@ -3622,6 +3685,7 @@ static struct iscsi_transport iscsi_tcp_transport = {
 	.destroy_conn		= iscsi_conn_destroy,
 	.set_param		= iscsi_conn_set_param,
 	.get_conn_param		= iscsi_conn_get_param,
+	.get_conn_str_param	= iscsi_conn_get_str_param,
 	.get_session_param	= iscsi_session_get_param,
 	.start_conn		= iscsi_conn_start,
 	.stop_conn		= iscsi_conn_stop,