[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>

7 files changed, 161 insertions, 37 deletions

diff --git a/drivers/scsi/scsi_tgt_if.c b/drivers/scsi/scsi_tgt_if.c
index ca22ddf81746..9815a1a2db24 100644
--- a/drivers/scsi/scsi_tgt_if.c
+++ b/drivers/scsi/scsi_tgt_if.c
@@ -102,7 +102,8 @@ static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
         return 0;
 }
 
-int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 tag)
+int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 itn_id,
+                             struct scsi_lun *lun, u64 tag)
 {
         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
         struct tgt_event ev;
@@ -110,6 +111,7 @@ int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 ta
 
         memset(&ev, 0, sizeof(ev));
         ev.p.cmd_req.host_no = shost->host_no;
+        ev.p.cmd_req.itn_id = itn_id;
         ev.p.cmd_req.data_len = cmd->request_bufflen;
         memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
         memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
@@ -127,7 +129,7 @@ int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 ta
         return err;
 }
 
-int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
+int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 itn_id, u64 tag)
 {
         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
         struct tgt_event ev;
@@ -135,6 +137,7 @@ int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
 
         memset(&ev, 0, sizeof(ev));
         ev.p.cmd_done.host_no = shost->host_no;
+        ev.p.cmd_done.itn_id = itn_id;
         ev.p.cmd_done.tag = tag;
         ev.p.cmd_done.result = cmd->result;
 
@@ -149,14 +152,15 @@ int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
         return err;
 }
 
-int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
-                                  struct scsi_lun *scsilun, void *data)
+int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 itn_id, int function,
+                                  u64 tag, struct scsi_lun *scsilun, void *data)
 {
         struct tgt_event ev;
         int err;
 
         memset(&ev, 0, sizeof(ev));
         ev.p.tsk_mgmt_req.host_no = host_no;
+        ev.p.tsk_mgmt_req.itn_id = itn_id;
         ev.p.tsk_mgmt_req.function = function;
         ev.p.tsk_mgmt_req.tag = tag;
         memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
@@ -172,6 +176,29 @@ int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
         return err;
 }
 
+int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 itn_id,
+                                          int function, char *initiator_id)
+{
+        struct tgt_event ev;
+        int err;
+
+        memset(&ev, 0, sizeof(ev));
+        ev.p.it_nexus_req.host_no = host_no;
+        ev.p.it_nexus_req.function = function;
+        ev.p.it_nexus_req.itn_id = itn_id;
+        if (initiator_id)
+                strncpy(ev.p.it_nexus_req.initiator_id, initiator_id,
+                        sizeof(ev.p.it_nexus_req.initiator_id));
+
+        dprintk("%d %x %llx\n", host_no, function, (unsigned long long)itn_id);
+
+        err = tgt_uspace_send_event(TGT_KEVENT_IT_NEXUS_REQ, &ev);
+        if (err)
+                eprintk("tx buf is full, could not send\n");
+
+        return err;
+}
+
 static int event_recv_msg(struct tgt_event *ev)
 {
         int err = 0;
@@ -179,6 +206,7 @@ static int event_recv_msg(struct tgt_event *ev)
         switch (ev->hdr.type) {
         case TGT_UEVENT_CMD_RSP:
                 err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
+                                           ev->p.cmd_rsp.itn_id,
                                            ev->p.cmd_rsp.result,
                                            ev->p.cmd_rsp.tag,
                                            ev->p.cmd_rsp.uaddr,
@@ -189,9 +217,15 @@ static int event_recv_msg(struct tgt_event *ev)
                 break;
         case TGT_UEVENT_TSK_MGMT_RSP:
                 err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
+                                               ev->p.tsk_mgmt_rsp.itn_id,
                                                ev->p.tsk_mgmt_rsp.mid,
                                                ev->p.tsk_mgmt_rsp.result);
                 break;
+        case TGT_UEVENT_IT_NEXUS_RSP:
+                err = scsi_tgt_kspace_it_nexus_rsp(ev->p.it_nexus_rsp.host_no,
+                                                   ev->p.it_nexus_rsp.itn_id,
+                                                   ev->p.it_nexus_rsp.result);
+                break;
         default:
                 eprintk("unknown type %d\n", ev->hdr.type);
                 err = -EINVAL;
diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index 371b69c110bc..fa79e54722db 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -27,6 +27,7 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
+#include <scsi/scsi_transport.h>
 #include <scsi/scsi_tgt.h>
 
 #include "scsi_tgt_priv.h"
@@ -46,6 +47,7 @@ struct scsi_tgt_cmd {
 
         struct list_head hash_list;
         struct request *rq;
+        u64 itn_id;
         u64 tag;
 };
 
@@ -185,12 +187,13 @@ static void scsi_tgt_cmd_destroy(struct work_struct *work)
 }
 
 static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd,
-                              u64 tag)
+                              u64 itn_id, u64 tag)
 {
         struct scsi_tgt_queuedata *qdata = rq->q->queuedata;
         unsigned long flags;
         struct list_head *head;
 
+        tcmd->itn_id = itn_id;
         tcmd->tag = tag;
         tcmd->bio = NULL;
         INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy);
@@ -301,14 +304,14 @@ EXPORT_SYMBOL_GPL(scsi_tgt_cmd_to_host);
  * @scsilun:    scsi lun
  * @tag:        unique value to identify this command for tmf
  */
-int scsi_tgt_queue_command(struct scsi_cmnd *cmd, struct scsi_lun *scsilun,
-                           u64 tag)
+int scsi_tgt_queue_command(struct scsi_cmnd *cmd, u64 itn_id,
+                           struct scsi_lun *scsilun, u64 tag)
 {
         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
         int err;
 
-        init_scsi_tgt_cmd(cmd->request, tcmd, tag);
-        err = scsi_tgt_uspace_send_cmd(cmd, scsilun, tag);
+        init_scsi_tgt_cmd(cmd->request, tcmd, itn_id, tag);
+        err = scsi_tgt_uspace_send_cmd(cmd, itn_id, scsilun, tag);
         if (err)
                 cmd_hashlist_del(cmd);
 
@@ -326,7 +329,7 @@ static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 
         dprintk("cmd %p %lu\n", cmd, rq_data_dir(cmd->request));
 
-        scsi_tgt_uspace_send_status(cmd, tcmd->tag);
+        scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 
         if (cmd->request_buffer)
                 scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
@@ -459,7 +462,7 @@ static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag)
         return rq;
 }
 
-int scsi_tgt_kspace_exec(int host_no, int result, u64 tag,
+int scsi_tgt_kspace_exec(int host_no, u64 itn_id, int result, u64 tag,
                          unsigned long uaddr, u32 len, unsigned long sense_uaddr,
                          u32 sense_len, u8 rw)
 {
@@ -541,21 +544,22 @@ done:
         return err;
 }
 
-int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, int function, u64 tag,
-                              struct scsi_lun *scsilun, void *data)
+int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, u64 itn_id,
+                              int function, u64 tag, struct scsi_lun *scsilun,
+                              void *data)
 {
         int err;
 
         /* TODO: need to retry if this fails. */
-        err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, function,
-                                            tag, scsilun, data);
+        err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, itn_id,
+                                            function, tag, scsilun, data);
         if (err < 0)
                 eprintk("The task management request lost!\n");
         return err;
 }
 EXPORT_SYMBOL_GPL(scsi_tgt_tsk_mgmt_request);
 
-int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 mid, int result)
+int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 itn_id, u64 mid, int result)
 {
         struct Scsi_Host *shost;
         int err = -EINVAL;
@@ -573,7 +577,60 @@ int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 mid, int result)
                 goto done;
         }
 
-        err = shost->hostt->tsk_mgmt_response(mid, result);
+        err = shost->hostt->tsk_mgmt_response(shost, itn_id, mid, result);
+done:
+        scsi_host_put(shost);
+        return err;
+}
+
+int scsi_tgt_it_nexus_create(struct Scsi_Host *shost, u64 itn_id,
+                             char *initiator)
+{
+        int err;
+
+        /* TODO: need to retry if this fails. */
+        err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no, itn_id, 0,
+                                                    initiator);
+        if (err < 0)
+                eprintk("The i_t_neuxs request lost, %d %llx!\n",
+                        shost->host_no, (unsigned long long)itn_id);
+        return err;
+}
+EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_create);
+
+int scsi_tgt_it_nexus_destroy(struct Scsi_Host *shost, u64 itn_id)
+{
+        int err;
+
+        /* TODO: need to retry if this fails. */
+        err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no,
+                                                    itn_id, 1, NULL);
+        if (err < 0)
+                eprintk("The i_t_neuxs request lost, %d %llx!\n",
+                        shost->host_no, (unsigned long long)itn_id);
+        return err;
+}
+EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_destroy);
+
+int scsi_tgt_kspace_it_nexus_rsp(int host_no, u64 itn_id, int result)
+{
+        struct Scsi_Host *shost;
+        int err = -EINVAL;
+
+        dprintk("%d %d %llx\n", host_no, result, (unsigned long long) mid);
+
+        shost = scsi_host_lookup(host_no);
+        if (IS_ERR(shost)) {
+                printk(KERN_ERR "Could not find host no %d\n", host_no);
+                return err;
+        }
+
+        if (!shost->uspace_req_q) {
+                printk(KERN_ERR "Not target scsi host %d\n", host_no);
+                goto done;
+        }
+
+        err = shost->transportt->it_nexus_response(shost, itn_id, result);
 done:
         scsi_host_put(shost);
         return err;
diff --git a/drivers/scsi/scsi_tgt_priv.h b/drivers/scsi/scsi_tgt_priv.h
index e9e6db1c417f..cb92888948f9 100644
--- a/drivers/scsi/scsi_tgt_priv.h
+++ b/drivers/scsi/scsi_tgt_priv.h
@@ -15,12 +15,18 @@ do {								\
 extern void scsi_tgt_if_exit(void);
 extern int scsi_tgt_if_init(void);
 
-extern int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun,
-                                    u64 tag);
-extern int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag);
-extern int scsi_tgt_kspace_exec(int host_no, int result, u64 tag,
-                                unsigned long uaddr, u32 len, unsigned long sense_uaddr,
-                                u32 sense_len, u8 rw);
-extern int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
+extern int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 it_nexus_id,
+                                    struct scsi_lun *lun, u64 tag);
+extern int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 it_nexus_id,
+                                       u64 tag);
+extern int scsi_tgt_kspace_exec(int host_no, u64 it_nexus_id, int result, u64 tag,
+                                unsigned long uaddr, u32 len,
+                                unsigned long sense_uaddr, u32 sense_len, u8 rw);
+extern int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 it_nexus_id,
+                                         int function, u64 tag,
                                          struct scsi_lun *scsilun, void *data);
-extern int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 mid, int result);
+extern int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 it_nexus_id,
+                                    u64 mid, int result);
+extern int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 it_nexus_id,
+                                                 int function, char *initiator);
+extern int scsi_tgt_kspace_it_nexus_rsp(int host_no, u64 it_nexus_id, int result);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 3b8a6a85c2f8..89c40c4bd5c4 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -146,7 +146,7 @@ struct scsi_host_template {
                                   void (*done)(struct scsi_cmnd *));
 
         /* Used as callback for the completion of task management request. */
-        int (* tsk_mgmt_response)(u64 mid, int result);
+        int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64 mid, int result);
 
         /*
          * This is an error handling strategy routine.  You don't need to
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);
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))));
 
diff --git a/include/scsi/scsi_transport.h b/include/scsi/scsi_transport.h
index 3c18baa65a72..af5b3e15e64e 100644
--- a/include/scsi/scsi_transport.h
+++ b/include/scsi/scsi_transport.h
@@ -65,6 +65,12 @@ struct scsi_transport_template {
          * EH_NOT_HANDLED       Begin normal error recovery
          */
         enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+
+        /*
+         * Used as callback for the completion of i_t_nexus request
+         * for target drivers.
+         */
+        int (* it_nexus_response)(struct Scsi_Host *, u64, int);
 };
 
 #define transport_class_to_shost(tc) \