[SCSI] iscsi: add target discvery event to transport class

Patch from david.somayajulu@qlogic.com:

Add target discovery event. We may have a setup where the iscsi traffic
is on a different netowrk than the other network traffic. In this case
we will want to do discovery though the iscsi card. This patch adds
a event to the transport class that can be used by hw iscsi cards that
support this.

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

Author: Mike Christie

drivers/scsi/scsi_transport_iscsi.c

@@ -977,6 +977,21 @@ iscsi_if_transport_ep(struct iscsi_transport *transport,
 	return rc;
 }
 
+static int
+iscsi_tgt_dscvr(struct iscsi_transport *transport,
+		struct iscsi_uevent *ev)
+{
+	struct sockaddr *dst_addr;
+
+	if (!transport->tgt_dscvr)
+		return -EINVAL;
+
+	dst_addr = (struct sockaddr *)((char*)ev + sizeof(*ev));
+	return transport->tgt_dscvr(ev->u.tgt_dscvr.type,
+				    ev->u.tgt_dscvr.host_no,
+				    ev->u.tgt_dscvr.enable, dst_addr);
+}
+
 static int
 iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
@@ -1065,6 +1080,9 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
 		err = iscsi_if_transport_ep(transport, ev, nlh->nlmsg_type);
 		break;
+	case ISCSI_UEVENT_TGT_DSCVR:
+		err = iscsi_tgt_dscvr(transport, ev);
+		break;
 	default:
 		err = -EINVAL;
 		break;

include/scsi/iscsi_if.h

@@ -47,12 +47,20 @@ enum iscsi_uevent_e {
 	ISCSI_UEVENT_TRANSPORT_EP_POLL		= UEVENT_BASE + 13,
 	ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT	= UEVENT_BASE + 14,
 
+	ISCSI_UEVENT_TGT_DSCVR		= UEVENT_BASE + 15,
+
 	/* up events */
 	ISCSI_KEVENT_RECV_PDU		= KEVENT_BASE + 1,
 	ISCSI_KEVENT_CONN_ERROR		= KEVENT_BASE + 2,
 	ISCSI_KEVENT_IF_ERROR		= KEVENT_BASE + 3,
 };
 
+enum iscsi_tgt_dscvr {
+	ISCSI_TGT_DSCVR_SEND_TARGETS	= 1,
+	ISCSI_TGT_DSCVR_ISNS		= 2,
+	ISCSI_TGT_DSCVR_SLP		= 3,
+};
+
 struct iscsi_uevent {
 	uint32_t type; /* k/u events type */
 	uint32_t iferror; /* carries interface or resource errors */
@@ -116,6 +124,17 @@ struct iscsi_uevent {
 		struct msg_transport_disconnect {
 			uint64_t	ep_handle;
 		} ep_disconnect;
+		struct msg_tgt_dscvr {
+			enum iscsi_tgt_dscvr	type;
+			uint32_t	host_no;
+			/*
+ 			 * enable = 1 to establish a new connection
+			 * with the server. enable = 0 to disconnect
+			 * from the server. Used primarily to switch
+			 * from one iSNS server to another.
+			 */
+			uint32_t	enable;
+		} tgt_dscvr;
 	} u;
 	union {
 		/* messages k -> u */
@@ -141,6 +160,24 @@ struct iscsi_uevent {
 		struct msg_transport_connect_ret {
 			uint64_t	handle;
 		} ep_connect_ret;
+		struct msg_tgt_dscvr_ret {
+			/*
+			 * session/connection pair used to reference
+			 * the connection to server
+			 */
+			uint32_t	sid;
+			uint32_t	cid;
+			union {
+				struct isns {
+					/* port # for conn to iSNS server */
+					uint16_t isns_port;
+					/* listening port to receive SCNs */
+					uint16_t scn_port;
+					/* listening port to receive ESIs */
+					uint16_t esi_port;
+				} isns_attrib;
+			} u;
+		} tgt_dscvr_ret;
 	} r;
 } __attribute__ ((aligned (sizeof(uint64_t))));
 

include/scsi/scsi_transport_iscsi.h

@@ -127,6 +127,8 @@ struct iscsi_transport {
 			   uint64_t *ep_handle);
 	int (*ep_poll) (uint64_t ep_handle, int timeout_ms);
 	void (*ep_disconnect) (uint64_t ep_handle);
+	int (*tgt_dscvr) (enum iscsi_tgt_dscvr type, uint32_t host_no,
+			  uint32_t enable, struct sockaddr *dst_addr);
 };
 
 /*