IB/srp: Add orig_dgid sysfs attribute to scsi_host

Add an orig_dgid attribute in sysfs for SRP scsi_hosts, so that
userspace can tell what the original dgid value written to the
add_target file was, even if the connection is redirected to a
different port while connecting.

Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -1468,6 +1468,25 @@ static ssize_t show_dgid(struct class_device *cdev, char *buf)
 		       be16_to_cpu(((__be16 *) target->path.dgid.raw)[7]));
 }
 
+static ssize_t show_orig_dgid(struct class_device *cdev, char *buf)
+{
+	struct srp_target_port *target = host_to_target(class_to_shost(cdev));
+
+	if (target->state == SRP_TARGET_DEAD ||
+	    target->state == SRP_TARGET_REMOVED)
+		return -ENODEV;
+
+	return sprintf(buf, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+		       be16_to_cpu(target->orig_dgid[0]),
+		       be16_to_cpu(target->orig_dgid[1]),
+		       be16_to_cpu(target->orig_dgid[2]),
+		       be16_to_cpu(target->orig_dgid[3]),
+		       be16_to_cpu(target->orig_dgid[4]),
+		       be16_to_cpu(target->orig_dgid[5]),
+		       be16_to_cpu(target->orig_dgid[6]),
+		       be16_to_cpu(target->orig_dgid[7]));
+}
+
 static ssize_t show_zero_req_lim(struct class_device *cdev, char *buf)
 {
 	struct srp_target_port *target = host_to_target(class_to_shost(cdev));
@@ -1498,6 +1517,7 @@ static CLASS_DEVICE_ATTR(ioc_guid,	  S_IRUGO, show_ioc_guid,	 NULL);
 static CLASS_DEVICE_ATTR(service_id,	  S_IRUGO, show_service_id,	 NULL);
 static CLASS_DEVICE_ATTR(pkey,		  S_IRUGO, show_pkey,		 NULL);
 static CLASS_DEVICE_ATTR(dgid,		  S_IRUGO, show_dgid,		 NULL);
+static CLASS_DEVICE_ATTR(orig_dgid,	  S_IRUGO, show_orig_dgid,	 NULL);
 static CLASS_DEVICE_ATTR(zero_req_lim,	  S_IRUGO, show_zero_req_lim,	 NULL);
 static CLASS_DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,	 NULL);
 static CLASS_DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);
@@ -1508,6 +1528,7 @@ static struct class_device_attribute *srp_host_attrs[] = {
 	&class_device_attr_service_id,
 	&class_device_attr_pkey,
 	&class_device_attr_dgid,
+	&class_device_attr_orig_dgid,
 	&class_device_attr_zero_req_lim,
 	&class_device_attr_local_ib_port,
 	&class_device_attr_local_ib_device,
@@ -1662,6 +1683,7 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
 				target->path.dgid.raw[i] = simple_strtoul(dgid, NULL, 16);
 			}
 			kfree(p);
+			memcpy(target->orig_dgid, target->path.dgid.raw, 16);
 			break;
 
 		case SRP_OPT_PKEY:

drivers/infiniband/ulp/srp/ib_srp.h

@@ -129,6 +129,7 @@ struct srp_target_port {
 	unsigned int		scsi_id;
 
 	struct ib_sa_path_rec	path;
+	__be16			orig_dgid[8];
 	struct ib_sa_query     *path_query;
 	int			path_query_id;