[SCSI] iscsi class, iscsi_tcp/iser: add host arg to session creation

iscsi offload (bnx2i and qla4xx) allocate a scsi host per hba,
so the session creation path needs a shost/host_no argument.
Software iscsi/iser will follow the same behabior as before
where it allcoates a host per session, but in the future iser
will probably look more like bnx2i where the host's parent is
the hardware (rnic for iser and for bnx2i it is the nic), because
it does not use a socket layer like how iscsi_tcp does.

Signed-off-by: Mike Christie <[email protected]>
Signed-off-by: James Bottomley <[email protected]>

Author: Mike Christie

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -368,6 +368,7 @@ static struct iscsi_transport iscsi_iser_transport;
 static struct iscsi_cls_session *
 iscsi_iser_session_create(struct iscsi_transport *iscsit,
 			 struct scsi_transport_template *scsit,
+			 struct Scsi_Host *shost,
 			 uint16_t cmds_max, uint16_t qdepth,
 			 uint32_t initial_cmdsn, uint32_t *hostno)
 {

drivers/scsi/iscsi_tcp.c

@@ -1871,8 +1871,9 @@ iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
 static struct iscsi_cls_session *
 iscsi_tcp_session_create(struct iscsi_transport *iscsit,
 			 struct scsi_transport_template *scsit,
-			 uint16_t cmds_max, uint16_t qdepth,
-			 uint32_t initial_cmdsn, uint32_t *hostno)
+			 struct Scsi_Host *shost, uint16_t cmds_max,
+			 uint16_t qdepth, uint32_t initial_cmdsn,
+			 uint32_t *hostno)
 {
 	struct iscsi_cls_session *cls_session;
 	struct iscsi_session *session;

drivers/scsi/scsi_transport_iscsi.c

@@ -1017,21 +1017,38 @@ int iscsi_session_event(struct iscsi_cls_session *session,
 EXPORT_SYMBOL_GPL(iscsi_session_event);
 
 static int
-iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
+iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev,
+			uint32_t host_no, uint32_t initial_cmdsn,
+			uint16_t cmds_max, uint16_t queue_depth)
 {
 	struct iscsi_transport *transport = priv->iscsi_transport;
 	struct iscsi_cls_session *session;
-	uint32_t hostno;
+	struct Scsi_Host *shost = NULL;
 
-	session = transport->create_session(transport, &priv->t,
-					    ev->u.c_session.cmds_max,
-					    ev->u.c_session.queue_depth,
-					    ev->u.c_session.initial_cmdsn,
-					    &hostno);
+	/*
+	 * Software iscsi allocates a host per session, but
+	 * offload drivers (and possibly iser one day) allocate a host per
+	 * hba/nic/rnic. Offload will match a host here, but software will
+	 * return a new hostno after the create_session callback has returned.
+	 */
+	if (host_no != UINT_MAX) {
+		shost = scsi_host_lookup(host_no);
+		if (IS_ERR(shost)) {
+			printk(KERN_ERR "Could not find host no %u to "
+			       "create session\n", host_no);
+			return -ENODEV;
+		}
+	}
+
+	session = transport->create_session(transport, &priv->t, shost,
+					    cmds_max, queue_depth,
+					    initial_cmdsn, &host_no);
+	if (shost)
+		scsi_host_put(shost);
 	if (!session)
 		return -ENOMEM;
 
-	ev->r.c_session_ret.host_no = hostno;
+	ev->r.c_session_ret.host_no = host_no;
 	ev->r.c_session_ret.sid = session->sid;
 	return 0;
 }
@@ -1190,6 +1207,7 @@ static int
 iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	int err = 0;
+	uint32_t host_no = UINT_MAX;
 	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
 	struct iscsi_transport *transport = NULL;
 	struct iscsi_internal *priv;
@@ -1208,7 +1226,17 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 	switch (nlh->nlmsg_type) {
 	case ISCSI_UEVENT_CREATE_SESSION:
-		err = iscsi_if_create_session(priv, ev);
+		err = iscsi_if_create_session(priv, ev, host_no,
+					      ev->u.c_session.initial_cmdsn,
+					      ev->u.c_session.cmds_max,
+					      ev->u.c_session.queue_depth);
+		break;
+	case ISCSI_UEVENT_CREATE_BOUND_SESSION:
+		err = iscsi_if_create_session(priv, ev,
+					ev->u.c_bound_session.host_no,
+					ev->u.c_bound_session.initial_cmdsn,
+					ev->u.c_bound_session.cmds_max,
+					ev->u.c_bound_session.queue_depth);
 		break;
 	case ISCSI_UEVENT_DESTROY_SESSION:
 		session = iscsi_session_lookup(ev->u.d_session.sid);

include/scsi/iscsi_if.h

@@ -50,6 +50,7 @@ enum iscsi_uevent_e {
 	ISCSI_UEVENT_TGT_DSCVR		= UEVENT_BASE + 15,
 	ISCSI_UEVENT_SET_HOST_PARAM	= UEVENT_BASE + 16,
 	ISCSI_UEVENT_UNBIND_SESSION	= UEVENT_BASE + 17,
+	ISCSI_UEVENT_CREATE_BOUND_SESSION	= UEVENT_BASE + 18,
 
 	/* up events */
 	ISCSI_KEVENT_RECV_PDU		= KEVENT_BASE + 1,
@@ -78,6 +79,12 @@ struct iscsi_uevent {
 			uint16_t	cmds_max;
 			uint16_t	queue_depth;
 		} c_session;
+		struct msg_create_bound_session {
+			uint32_t	host_no;
+			uint32_t	initial_cmdsn;
+			uint16_t	cmds_max;
+			uint16_t	queue_depth;
+		} c_bound_session;
 		struct msg_destroy_session {
 			uint32_t	sid;
 		} d_session;

include/scsi/libiscsi.h

@@ -24,6 +24,7 @@
 #define LIBISCSI_H
 
 #include <linux/types.h>
+#include <linux/wait.h>
 #include <linux/mutex.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>

include/scsi/scsi_transport_iscsi.h

@@ -92,8 +92,8 @@ struct iscsi_transport {
 	unsigned int max_conn;
 	unsigned int max_cmd_len;
 	struct iscsi_cls_session *(*create_session) (struct iscsi_transport *it,
-		struct scsi_transport_template *t, uint16_t, uint16_t,
-		uint32_t sn, uint32_t *hn);
+		struct scsi_transport_template *t, struct Scsi_Host *shost,
+		uint16_t cmds_max, uint16_t qdepth, 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);