[SCSI] iscsi: rm kernel iscsi handles usage for session and connection

from hare@suse.de and michaelc@cs.wisc.edu

hw iscsi like qla4xxx does not allocate a host per session and
for userspace it is difficult to restart iscsid using the
"iscsi handles" for the session and connection, so this
patch just has the class or userspace allocate the id for
the session and connection.

Note: this breaks userspace and requires users to upgrade to the newest
open-iscsi tools. Sorry about his but open-iscsi is still too new to
say we have a stable user-kernel api and we were not good nough
designers to know that other hw iscsi drivers and iscsid itself would
need such changes. Actually we sorta did but at the time we did not
have the HW available to us so we could only guess.

Luckily, the only tools hooking into the class are the open-iscsi ones
or other tools like iscsitart hook into the open-iscsi engine from
userspace or prgroams like anaconda call our tools so they are not affected.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/iscsi_tcp.c

@@ -3254,7 +3254,7 @@ static struct iscsi_transport iscsi_tcp_transport;
 
 static struct iscsi_cls_session *
 iscsi_session_create(struct scsi_transport_template *scsit,
-		     uint32_t initial_cmdsn, uint32_t *sid)
+		     uint32_t initial_cmdsn, uint32_t *hostno)
 {
 	struct Scsi_Host *shost;
 	struct iscsi_session *session;
@@ -3274,7 +3274,8 @@ iscsi_session_create(struct scsi_transport_template *scsit,
 	session->exp_cmdsn = initial_cmdsn + 1;
 	session->max_cmdsn = initial_cmdsn + 1;
 	session->max_r2t = 1;
-	*sid = shost->host_no;
+
+	*hostno = shost->host_no;
 
 	/* initialize SCSI PDU commands pool */
 	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,

include/scsi/iscsi_if.h

@@ -60,59 +60,68 @@ struct iscsi_uevent {
 			uint32_t	initial_cmdsn;
 		} c_session;
 		struct msg_destroy_session {
-			uint64_t	session_handle;
 			uint32_t	sid;
 		} d_session;
 		struct msg_create_conn {
-			uint64_t	session_handle;
-			uint32_t	cid;
 			uint32_t	sid;
+			uint32_t	cid;
 		} c_conn;
 		struct msg_bind_conn {
-			uint64_t	session_handle;
-			uint64_t	conn_handle;
+			uint32_t	sid;
+			uint32_t	cid;
 			uint32_t	transport_fd;
 			uint32_t	is_leading;
 		} b_conn;
 		struct msg_destroy_conn {
-			uint64_t	conn_handle;
+			uint32_t	sid;
 			uint32_t	cid;
 		} d_conn;
 		struct msg_send_pdu {
+			uint32_t	sid;
+			uint32_t	cid;
 			uint32_t	hdr_size;
 			uint32_t	data_size;
-			uint64_t	conn_handle;
 		} send_pdu;
 		struct msg_set_param {
-			uint64_t	conn_handle;
+			uint32_t	sid;
+			uint32_t	cid;
 			uint32_t	param; /* enum iscsi_param */
 			uint32_t	value;
 		} set_param;
 		struct msg_start_conn {
-			uint64_t	conn_handle;
+			uint32_t	sid;
+			uint32_t	cid;
 		} start_conn;
 		struct msg_stop_conn {
+			uint32_t	sid;
+			uint32_t	cid;
 			uint64_t	conn_handle;
 			uint32_t	flag;
 		} stop_conn;
 		struct msg_get_stats {
-			uint64_t	conn_handle;
+			uint32_t	sid;
+			uint32_t	cid;
 		} get_stats;
 	} u;
 	union {
 		/* messages k -> u */
-		uint64_t		handle;
 		int			retcode;
 		struct msg_create_session_ret {
-			uint64_t	session_handle;
 			uint32_t	sid;
+			uint32_t	host_no;
 		} c_session_ret;
+		struct msg_create_conn_ret {
+			uint32_t	sid;
+			uint32_t	cid;
+		} c_conn_ret;
 		struct msg_recv_req {
+			uint32_t	sid;
+			uint32_t	cid;
 			uint64_t	recv_handle;
-			uint64_t	conn_handle;
 		} recv_req;
 		struct msg_conn_error {
-			uint64_t	conn_handle;
+			uint32_t	sid;
+			uint32_t	cid;
 			uint32_t	error; /* enum iscsi_err */
 		} connerror;
 	} r;

include/scsi/scsi_transport_iscsi.h

@@ -60,11 +60,13 @@ struct iscsi_transport {
 	int ihostdata_size;
 	/* LLD connection data size */
 	int conndata_size;
+	/* LLD session data size */
+	int sessiondata_size;
 	int max_lun;
 	unsigned int max_conn;
 	unsigned int max_cmd_len;
 	struct iscsi_cls_session *(*create_session)
-		(struct scsi_transport_template *t, uint32_t sn, uint32_t *sid);
+		(struct scsi_transport_template *t, uint32_t sn, uint32_t *hn);
 	void (*destroy_session) (struct iscsi_cls_session *session);
 	struct iscsi_cls_conn *(*create_conn) (struct iscsi_cls_session *sess,
 				uint32_t cid);
@@ -104,6 +106,7 @@ struct iscsi_cls_conn {
 	struct list_head conn_list;	/* item in connlist */
 	void *dd_data;			/* LLD private data */
 	struct iscsi_transport *transport;
+	uint32_t cid;			/* connection id */
 	int active;			/* must be accessed with the connlock */
 	struct device dev;		/* sysfs transport/container device */
 	struct mempool_zone *z_error;
@@ -117,6 +120,8 @@ struct iscsi_cls_conn {
 struct iscsi_cls_session {
 	struct list_head sess_list;		/* item in session_list */
 	struct iscsi_transport *transport;
+	int sid;				/* session id */
+	void *dd_data;				/* LLD private data */
 	struct device dev;	/* sysfs transport/container device */
 };