usb: gadget: let f_* use usb_string_ids_tab() where it makes sense

Instead of calling usb_string_id() multiple times I replace it with one
usb_string_ids_tab(). The NULL pointer in struct usb_string with "" and
are not overwritten in fail or unbind case.

The conditional assignment remains because some gadgets recycle the string
ID because the same descriptor (and string ID) is used if we have more
than one config descriptor.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 9 insertions, 33 deletions

diff --git a/drivers/usb/gadget/f_ecm.c b/drivers/usb/gadget/f_ecm.c
index 2d3c5a4..83420a3 100644
--- a/drivers/usb/gadget/f_ecm.c
+++ b/drivers/usb/gadget/f_ecm.c
@@ -354,7 +354,7 @@ static struct usb_descriptor_header *ecm_ss_function[] = {
 
 static struct usb_string ecm_string_defs[] = {
 	[0].s = "CDC Ethernet Control Model (ECM)",
-	[1].s = NULL /* DYNAMIC */,
+	[1].s = "",
 	[2].s = "CDC Ethernet Data",
 	[3].s = "CDC ECM",
 	{  } /* end of list */
@@ -803,12 +803,11 @@ ecm_unbind(struct usb_configuration *c, struct usb_function *f)
 
 	DBG(c->cdev, "ecm unbind\n");
 
+	ecm_string_defs[0].id = 0;
 	usb_free_all_descriptors(f);
 
 	kfree(ecm->notify_req->buf);
 	usb_ep_free_request(ecm->notify, ecm->notify_req);
-
-	ecm_string_defs[1].s = NULL;
 	kfree(ecm);
 }
 
@@ -833,36 +832,15 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 	if (!can_support_ecm(c->cdev->gadget) || !ethaddr)
 		return -EINVAL;
 
-	/* maybe allocate device-global string IDs */
 	if (ecm_string_defs[0].id == 0) {
-
-		/* control interface label */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
+		status = usb_string_ids_tab(c->cdev, ecm_string_defs);
+		if (status)
 			return status;
-		ecm_string_defs[0].id = status;
-		ecm_control_intf.iInterface = status;
 
-		/* data interface label */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ecm_string_defs[2].id = status;
-		ecm_data_intf.iInterface = status;
-
-		/* MAC address */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ecm_string_defs[1].id = status;
-		ecm_desc.iMACAddress = status;
-
-		/* IAD label */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ecm_string_defs[3].id = status;
-		ecm_iad_descriptor.iFunction = status;
+		ecm_control_intf.iInterface = ecm_string_defs[0].id;
+		ecm_data_intf.iInterface = ecm_string_defs[2].id;
+		ecm_desc.iMACAddress = ecm_string_defs[1].id;
+		ecm_iad_descriptor.iFunction = ecm_string_defs[3].id;
 	}
 
 	/* allocate and initialize one new instance */
@@ -887,9 +865,7 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 	ecm->port.func.disable = ecm_disable;
 
 	status = usb_add_function(c, &ecm->port.func);
-	if (status) {
-		ecm_string_defs[1].s = NULL;
+	if (status)
 		kfree(ecm);
-	}
 	return status;
 }