[SCSI] srp_transport: add target driver support

This adds minimum target driver support:

- srp_rport_{add,del} calls scsi_tgt_it_nexus_{create,destroy} for
target drivers.

- add a callback to notify target drivers of the nexus operation
results to srp_function_template.

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>

3 files changed, 27 insertions, 2 deletions

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 778dc0fb1e4f..8d4057ea27b1 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -291,7 +291,7 @@ source "drivers/scsi/libsas/Kconfig"
 
 config SCSI_SRP_ATTRS
         tristate "SRP Transport Attributes"
-        depends on SCSI
+        depends on SCSI && SCSI_TGT
         help
           If you wish to export transport-specific information about
           each attached SRP device to sysfs, say Y.
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 608abd8aef20..8e5b41ca181d 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -30,6 +30,7 @@
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_transport_srp.h>
+#include <scsi/scsi_tgt.h>
 
 struct srp_host_attrs {
         atomic_t next_port_id;
@@ -221,6 +222,17 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
                 return ERR_PTR(ret);
         }
 
+        if (ids->roles == SRP_RPORT_ROLE_INITIATOR) {
+                ret = scsi_tgt_it_nexus_create(shost, (unsigned long)rport,
+                                               rport->port_id);
+                if (ret) {
+                        device_del(&rport->dev);
+                        transport_destroy_device(&rport->dev);
+                        put_device(&rport->dev);
+                        return ERR_PTR(ret);
+                }
+        }
+
         transport_add_device(&rport->dev);
         transport_configure_device(&rport->dev);
 
@@ -238,6 +250,10 @@ void srp_rport_del(struct srp_rport *rport)
 {
         struct device *dev = &rport->dev;
 
+        if (rport->roles == SRP_RPORT_ROLE_INITIATOR)
+                scsi_tgt_it_nexus_destroy(dev_to_shost(dev->parent),
+                                          (unsigned long)rport);
+
         transport_remove_device(dev);
         device_del(dev);
         transport_destroy_device(dev);
@@ -264,6 +280,12 @@ void srp_remove_host(struct Scsi_Host *shost)
 }
 EXPORT_SYMBOL_GPL(srp_remove_host);
 
+static int srp_it_nexus_response(struct Scsi_Host *shost, u64 id, int result)
+{
+        struct srp_internal *i = to_srp_internal(shost->transportt);
+        return i->f->it_nexus_response(shost, id, result);
+}
+
 /**
  * srp_attach_transport  --  instantiate SRP transport template
  * @ft:         SRP transport class function template
@@ -278,6 +300,8 @@ srp_attach_transport(struct srp_function_template *ft)
         if (!i)
                 return NULL;
 
+        i->t.it_nexus_response = srp_it_nexus_response;
+
         i->t.host_size = sizeof(struct srp_host_attrs);
         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
         i->t.host_attrs.ac.class = &srp_host_class.class;
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index 08b4a28a77b8..a705dbc016b3 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -21,7 +21,8 @@ struct srp_rport {
 };
 
 struct srp_function_template {
-        /* later */
+        /* for target drivers */
+        int (* it_nexus_response)(struct Scsi_Host *, u64, int);
 };
 
 extern struct scsi_transport_template *