[SCSI] tgt: add I_T nexus support

tgt uses scsi_host as I_T nexus. This works for ibmvstgt because it
creates one scsi_host for one initiator. However, other target drivers
don't work like that.

This adds I_T nexus support, which enable one scsi_host to handle
multiple initiators. New scsi_tgt_it_nexus_create/destroy functions
are expected be called transport classes. For example, ibmvstgt
creates an initiator remote port, then the srp transport calls
tgt_it_nexus_create. tgt doesn't manages I_T nexus, instead it tells
tgtd, user-space daemon, to create a new I_T nexus.

On the receiving the response from tgtd, tgt calls
shost->transportt->it_nexus_response. transports should notify a
lld. The srp transport uses it_nexus_response callback in
srp_function_template to do that.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/include/scsi/scsi_tgt.h b/include/scsi/scsi_tgt.h
index 4f4427937af2..d0fefb96158f 100644
--- a/include/scsi/scsi_tgt.h
+++ b/include/scsi/scsi_tgt.h
@@ -11,9 +11,11 @@ struct scsi_lun;
 extern struct Scsi_Host *scsi_tgt_cmd_to_host(struct scsi_cmnd *);
 extern int scsi_tgt_alloc_queue(struct Scsi_Host *);
 extern void scsi_tgt_free_queue(struct Scsi_Host *);
-extern int scsi_tgt_queue_command(struct scsi_cmnd *, struct scsi_lun *, u64);
-extern int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *, int, u64, struct scsi_lun *,
-                                     void *);
+extern int scsi_tgt_queue_command(struct scsi_cmnd *, u64, struct scsi_lun *, u64);
+extern int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *, u64, int, u64,
+                                     struct scsi_lun *, void *);
 extern struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *,
                                                enum dma_data_direction, gfp_t);
 extern void scsi_host_put_command(struct Scsi_Host *, struct scsi_cmnd *);
+extern int scsi_tgt_it_nexus_create(struct Scsi_Host *, u64, char *);
+extern int scsi_tgt_it_nexus_destroy(struct Scsi_Host *, u64);