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, 10 insertions, 30 deletions

diff --git a/drivers/usb/gadget/f_ncm.c b/drivers/usb/gadget/f_ncm.c
index 326d7e6c297c..f1f66e9c76ba 100644
--- a/drivers/usb/gadget/f_ncm.c
+++ b/drivers/usb/gadget/f_ncm.c
@@ -321,7 +321,7 @@ static struct usb_descriptor_header *ncm_hs_function[] __initdata = {
 
 static struct usb_string ncm_string_defs[] = {
 	[STRING_CTRL_IDX].s = "CDC Network Control Model (NCM)",
-	[STRING_MAC_IDX].s = NULL /* DYNAMIC */,
+	[STRING_MAC_IDX].s = "",
 	[STRING_DATA_IDX].s = "CDC Network Data",
 	[STRING_IAD_IDX].s = "CDC NCM",
 	{  } /* end of list */
@@ -1262,12 +1262,12 @@ ncm_unbind(struct usb_configuration *c, struct usb_function *f)
 
 	DBG(c->cdev, "ncm unbind\n");
 
+	ncm_string_defs[0].id = 0;
 	usb_free_all_descriptors(f);
 
 	kfree(ncm->notify_req->buf);
 	usb_ep_free_request(ncm->notify, ncm->notify_req);
 
-	ncm_string_defs[1].s = NULL;
 	kfree(ncm);
 }
 
@@ -1291,37 +1291,19 @@ int __init ncm_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 (ncm_string_defs[0].id == 0) {
-
-		/* control interface label */
-		status = usb_string_id(c->cdev);
+		status = usb_string_ids_tab(c->cdev, ncm_string_defs);
 		if (status < 0)
 			return status;
-		ncm_string_defs[STRING_CTRL_IDX].id = status;
-		ncm_control_intf.iInterface = status;
+		ncm_control_intf.iInterface =
+			ncm_string_defs[STRING_CTRL_IDX].id;
 
-		/* data interface label */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ncm_string_defs[STRING_DATA_IDX].id = status;
+		status = ncm_string_defs[STRING_DATA_IDX].id;
 		ncm_data_nop_intf.iInterface = status;
 		ncm_data_intf.iInterface = status;
 
-		/* MAC address */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ncm_string_defs[STRING_MAC_IDX].id = status;
-		ecm_desc.iMACAddress = status;
-
-		/* IAD */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		ncm_string_defs[STRING_IAD_IDX].id = status;
-		ncm_iad_desc.iFunction = status;
+		ecm_desc.iMACAddress = ncm_string_defs[STRING_MAC_IDX].id;
+		ncm_iad_desc.iFunction = ncm_string_defs[STRING_IAD_IDX].id;
 	}
 
 	/* allocate and initialize one new instance */
@@ -1331,7 +1313,7 @@ int __init ncm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 
 	/* export host's Ethernet address in CDC format */
 	snprintf(ncm->ethaddr, sizeof ncm->ethaddr, "%pm", ethaddr);
-	ncm_string_defs[1].s = ncm->ethaddr;
+	ncm_string_defs[STRING_MAC_IDX].s = ncm->ethaddr;
 
 	spin_lock_init(&ncm->lock);
 	ncm_reset_values(ncm);
@@ -1351,9 +1333,7 @@ int __init ncm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 	ncm->port.unwrap = ncm_unwrap_ntb;
 
 	status = usb_add_function(c, &ncm->port.func);
-	if (status) {
-		ncm_string_defs[1].s = NULL;
+	if (status)
 		kfree(ncm);
-	}
 	return status;
 }