[SCSI] iscsi class, iscsi_tcp, iser, qla4xxx: add netdevname sysfs attr

iSCSI must support software iscsi (iscsi_tcp, iser), hardware iscsi (qla4xxx),
and partial offload (broadcom). To be able to allow each stack or driver
or port (virtual or physical) to be able to log into the same target portal
we use the initiator tuple [[HWADDRESS | NETDEVNAME], INITIATOR_NAME] and
the target tuple [TARGETNAME, CONN_ADDRESS, CONN_PORT] to id a session.
This patch adds the netdev name, which is used by software iscsi when
it binds a session to a netdevice using the SO_BINDTODEVICE sock opt.
It cannot use HWADDRESS because if someone did vlans then the same netdevice
will have the same mac and the initiator,target id will not be unique.

Signed-off-by: Mike Christie <[e-mail]>
Cc: Roland Dreier <[e-mail]>
Cc: David C Somayajulu <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/infiniband/ulp/iser/iscsi_iser.c

···
 				  ISCSI_USERNAME | ISCSI_PASSWORD |
 				  ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN,
 	.host_param_mask	= ISCSI_HOST_HWADDRESS |
+				  ISCSI_HOST_NETDEV_NAME |
 				  ISCSI_HOST_INITIATOR_NAME,
 	.host_template          = &iscsi_iser_sht,
 	.conndata_size		= sizeof(struct iscsi_conn),

drivers/scsi/iscsi_tcp.c

···
 				  ISCSI_USERNAME | ISCSI_PASSWORD |
 				  ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN,
 	.host_param_mask	= ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
-				  ISCSI_HOST_INITIATOR_NAME,
+				  ISCSI_HOST_INITIATOR_NAME |
+				  ISCSI_HOST_NETDEV_NAME,
 	.host_template		= &iscsi_sht,
 	.conndata_size		= sizeof(struct iscsi_conn),
 	.max_conn		= 1,

drivers/scsi/libiscsi.c

···
 	kfree(session->username);
 	kfree(session->username_in);
 	kfree(session->targetname);
+	kfree(session->netdev);
 	kfree(session->hwaddress);
 	kfree(session->initiatorname);
 
···
 	int len;
 
 	switch (param) {
+	case ISCSI_HOST_PARAM_NETDEV_NAME:
+		if (!session->netdev)
+			len = sprintf(buf, "%s\n", "default");
+		else
+			len = sprintf(buf, "%s\n", session->netdev);
+		break;
 	case ISCSI_HOST_PARAM_HWADDRESS:
 		if (!session->hwaddress)
 			len = sprintf(buf, "%s\n", "default");
···
 	struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
 
 	switch (param) {
+	case ISCSI_HOST_PARAM_NETDEV_NAME:
+		if (!session->netdev)
+			session->netdev = kstrdup(buf, GFP_KERNEL);
+		break;
 	case ISCSI_HOST_PARAM_HWADDRESS:
 		if (!session->hwaddress)
 			session->hwaddress = kstrdup(buf, GFP_KERNEL);

drivers/scsi/qla4xxx/ql4_os.c

···
 static struct iscsi_transport qla4xxx_iscsi_transport = {
 	.owner			= THIS_MODULE,
 	.name			= DRIVER_NAME,
-	.caps			= CAP_FW_DB | CAP_SENDTARGETS_OFFLOAD,
+	.caps			= CAP_FW_DB | CAP_SENDTARGETS_OFFLOAD |
+				  CAP_DATA_PATH_OFFLOAD,
 	.param_mask		= ISCSI_CONN_PORT | ISCSI_CONN_ADDRESS |
 				  ISCSI_TARGET_NAME | ISCSI_TPGT,
 	.host_param_mask	= ISCSI_HOST_HWADDRESS |

drivers/scsi/scsi_transport_iscsi.c

···
 
 #define ISCSI_SESSION_ATTRS 15
 #define ISCSI_CONN_ATTRS 11
-#define ISCSI_HOST_ATTRS 3
+#define ISCSI_HOST_ATTRS 4
 #define ISCSI_TRANSPORT_VERSION "2.0-724"
 
 struct iscsi_internal {
···
 static ISCSI_CLASS_ATTR(host, field, S_IRUGO, show_host_param_##param,	\
 			NULL);
 
-iscsi_host_attr(ipaddress, ISCSI_HOST_PARAM_IPADDRESS);
+iscsi_host_attr(netdev, ISCSI_HOST_PARAM_NETDEV_NAME);
 iscsi_host_attr(hwaddress, ISCSI_HOST_PARAM_HWADDRESS);
+iscsi_host_attr(ipaddress, ISCSI_HOST_PARAM_IPADDRESS);
 iscsi_host_attr(initiatorname, ISCSI_HOST_PARAM_INITIATOR_NAME);
 
 #define SETUP_PRIV_SESSION_RD_ATTR(field)				\
···
 	priv->t.host_size = sizeof(struct iscsi_host);
 	transport_container_register(&priv->t.host_attrs);
 
+	SETUP_HOST_RD_ATTR(netdev, ISCSI_HOST_NETDEV_NAME);
 	SETUP_HOST_RD_ATTR(ipaddress, ISCSI_HOST_IPADDRESS);
 	SETUP_HOST_RD_ATTR(hwaddress, ISCSI_HOST_HWADDRESS);
 	SETUP_HOST_RD_ATTR(initiatorname, ISCSI_HOST_INITIATOR_NAME);

include/scsi/iscsi_if.h

···
 enum iscsi_host_param {
 	ISCSI_HOST_PARAM_HWADDRESS,
 	ISCSI_HOST_PARAM_INITIATOR_NAME,
+	ISCSI_HOST_PARAM_NETDEV_NAME,
 	ISCSI_HOST_PARAM_IPADDRESS,
 	ISCSI_HOST_PARAM_MAX,
 };
 
 #define ISCSI_HOST_HWADDRESS		(1 << ISCSI_HOST_PARAM_HWADDRESS)
 #define ISCSI_HOST_INITIATOR_NAME	(1 << ISCSI_HOST_PARAM_INITIATOR_NAME)
+#define ISCSI_HOST_NETDEV_NAME		(1 << ISCSI_HOST_PARAM_NETDEV_NAME)
 #define ISCSI_HOST_IPADDRESS		(1 << ISCSI_HOST_PARAM_IPADDRESS)
 
 #define iscsi_ptr(_handle) ((void*)(unsigned long)_handle)
···
 #define CAP_MARKERS		0x100
 #define CAP_FW_DB		0x200
 #define CAP_SENDTARGETS_OFFLOAD	0x400
+#define CAP_DATA_PATH_OFFLOAD	0x800
 
 /*
  * These flags describes reason of stop_conn() call

include/scsi/libiscsi.h

···
 	char			*password_in;
 	char			*targetname;
 	char			*initiatorname;
-	/* hw address being used for iscsi connection */
+	/* hw address or netdev iscsi connection is bound to */
 	char			*hwaddress;
+	char			*netdev;
 	/* control data */
 	struct iscsi_transport	*tt;
 	struct Scsi_Host	*host;