[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, 27 insertions, 8 deletions

diff --git a/include/scsi/scsi_tgt_if.h b/include/scsi/scsi_tgt_if.h
index 4cf9dff29a2f..f2ee7c238a45 100644
--- a/include/scsi/scsi_tgt_if.h
+++ b/include/scsi/scsi_tgt_if.h
@@ -23,13 +23,15 @@
 #define __SCSI_TARGET_IF_H
 
 /* user -> kernel */
-#define TGT_UEVENT_CMD_RSP      0x0001
-#define TGT_UEVENT_TSK_MGMT_RSP 0x0002
+#define TGT_UEVENT_CMD_RSP              0x0001
+#define TGT_UEVENT_IT_NEXUS_RSP         0x0002
+#define TGT_UEVENT_TSK_MGMT_RSP         0x0003
 
 /* kernel -> user */
-#define TGT_KEVENT_CMD_REQ      0x1001
-#define TGT_KEVENT_CMD_DONE     0x1002
-#define TGT_KEVENT_TSK_MGMT_REQ 0x1003
+#define TGT_KEVENT_CMD_REQ              0x1001
+#define TGT_KEVENT_CMD_DONE             0x1002
+#define TGT_KEVENT_IT_NEXUS_REQ         0x1003
+#define TGT_KEVENT_TSK_MGMT_REQ         0x1004
 
 struct tgt_event_hdr {
         uint16_t version;
@@ -46,6 +48,7 @@ struct tgt_event {
                 struct {
                         int host_no;
                         int result;
+                        aligned_u64 itn_id;
                         aligned_u64 tag;
                         aligned_u64 uaddr;
                         aligned_u64 sense_uaddr;
@@ -55,15 +58,22 @@ struct tgt_event {
                 } cmd_rsp;
                 struct {
                         int host_no;
-                        aligned_u64 mid;
                         int result;
+                        aligned_u64 itn_id;
+                        aligned_u64 mid;
                 } tsk_mgmt_rsp;
-
+                struct {
+                        __s32 host_no;
+                        __s32 result;
+                        aligned_u64 itn_id;
+                        __u32 function;
+                } it_nexus_rsp;
 
                 /* kernel -> user */
                 struct {
                         int host_no;
                         uint32_t data_len;
+                        aligned_u64 itn_id;
                         uint8_t scb[16];
                         uint8_t lun[8];
                         int attribute;
@@ -71,16 +81,25 @@ struct tgt_event {
                 } cmd_req;
                 struct {
                         int host_no;
-                        aligned_u64 tag;
                         int result;
+                        aligned_u64 itn_id;
+                        aligned_u64 tag;
                 } cmd_done;
                 struct {
                         int host_no;
                         int function;
+                        aligned_u64 itn_id;
                         aligned_u64 tag;
                         uint8_t lun[8];
                         aligned_u64 mid;
                 } tsk_mgmt_req;
+                struct {
+                        __s32 host_no;
+                        __u32 function;
+                        aligned_u64 itn_id;
+                        __u32 max_cmds;
+                        __u8 initiator_id[16];
+                } it_nexus_req;
         } p;
 } __attribute__ ((aligned (sizeof(uint64_t))));