Merge branch 'usb_cdc_fixes'

Bjørn Mork says:

====================
The 2 first patches in this series are required to make the Sierra
Wireless MC7710 card work in MBIM mode.  They may also be
required for other Qualcomm firmware based MBIM devices.

Patch #1 was previously posted as a standalone patch.  This version
is a replacement, removing a theoretical NULL pointer exception.

Patch #3 fixes a bug I introduced in v3.7
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/cdc_mbim.c

@@ -366,7 +366,7 @@ err:
 
 static const struct driver_info cdc_mbim_info = {
 	.description = "CDC MBIM",
-	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
+	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,

drivers/net/usb/cdc_ncm.c

@@ -344,6 +344,23 @@ static const struct ethtool_ops cdc_ncm_ethtool_ops = {
 	.nway_reset = usbnet_nway_reset,
 };
 
+/* return first slave interface if an IAD matches the given master */
+static struct usb_interface *get_iad_slave(struct usb_device *udev,
+					   struct usb_interface *master) {
+	int i;
+	struct usb_interface_assoc_descriptor *iad;
+	u8 mnum = master->cur_altsetting->desc.bInterfaceNumber;
+
+	for (i = 0; i < USB_MAXIADS; i++) {
+		iad = udev->actconfig->intf_assoc[i];
+		if (!iad)
+			break;
+		if (iad->bFirstInterface == mnum && iad->bInterfaceCount == 2)
+			return usb_ifnum_to_if(udev, mnum + 1);
+	}
+	return NULL;
+}
+
 int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting)
 {
 	struct cdc_ncm_ctx *ctx;
@@ -435,6 +452,16 @@ advance:
 		len -= temp;
 	}
 
+	/* some buggy devices have an IAD but no CDC Union */
+	if (!ctx->union_desc) {
+		dev_dbg(&intf->dev, "missing CDC Union descriptor\n");
+		ctx->data = get_iad_slave(dev->udev, intf);
+		if (ctx->data) {
+			ctx->control = intf;
+			dev_dbg(&intf->dev, "got slave from IAD\n");
+		}
+	}
+
 	/* check if we got everything */
 	if ((ctx->control == NULL) || (ctx->data == NULL) ||
 	    ((!ctx->mbim_desc) && ((ctx->ether_desc == NULL) || (ctx->control != intf))))
@@ -497,7 +524,8 @@ advance:
 error2:
 	usb_set_intfdata(ctx->control, NULL);
 	usb_set_intfdata(ctx->data, NULL);
-	usb_driver_release_interface(driver, ctx->data);
+	if (ctx->data != ctx->control)
+		usb_driver_release_interface(driver, ctx->data);
 error:
 	cdc_ncm_free((struct cdc_ncm_ctx *)dev->data[0]);
 	dev->data[0] = 0;