2 files changed, 34 insertions, 2 deletions

diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index bbde9884ab8a..8973abdec9f6 100644
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -158,7 +158,7 @@ static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
 	if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
 		goto err;
 
-	ret = cdc_ncm_bind_common(dev, intf, data_altsetting, 0);
+	ret = cdc_ncm_bind_common(dev, intf, data_altsetting, dev->driver_info->data);
 	if (ret)
 		goto err;
 
@@ -582,6 +582,26 @@ static const struct driver_info cdc_mbim_info_zlp = {
 	.tx_fixup = cdc_mbim_tx_fixup,
 };
 
+/* The spefication explicitly allows NDPs to be placed anywhere in the
+ * frame, but some devices fail unless the NDP is placed after the IP
+ * packets.  Using the CDC_NCM_FLAG_NDP_TO_END flags to force this
+ * behaviour.
+ *
+ * Note: The current implementation of this feature restricts each NTB
+ * to a single NDP, implying that multiplexed sessions cannot share an
+ * NTB. This might affect performace for multiplexed sessions.
+ */
+static const struct driver_info cdc_mbim_info_ndp_to_end = {
+	.description = "CDC MBIM",
+	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
+	.bind = cdc_mbim_bind,
+	.unbind = cdc_mbim_unbind,
+	.manage_power = cdc_mbim_manage_power,
+	.rx_fixup = cdc_mbim_rx_fixup,
+	.tx_fixup = cdc_mbim_tx_fixup,
+	.data = CDC_NCM_FLAG_NDP_TO_END,
+};
+
 static const struct usb_device_id mbim_devs[] = {
 	/* This duplicate NCM entry is intentional. MBIM devices can
 	 * be disguised as NCM by default, and this is necessary to
@@ -597,6 +617,10 @@ static const struct usb_device_id mbim_devs[] = {
 	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info,
 	},
+	/* Huawei E3372 fails unless NDP comes after the IP packets */
+	{ USB_DEVICE_AND_INTERFACE_INFO(0x12d1, 0x157d, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
+	  .driver_info = (unsigned long)&cdc_mbim_info_ndp_to_end,
+	},
 	/* default entry */
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_zlp,
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 3b1ba8237768..1e9843a41168 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -955,10 +955,18 @@ static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_
 	* NTH16 header as we would normally do. NDP isn't written to the SKB yet, and
 	* the wNdpIndex field in the header is actually not consistent with reality. It will be later.
 	*/
-	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)
+	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
 		if (ctx->delayed_ndp16->dwSignature == sign)
 			return ctx->delayed_ndp16;
 
+		/* We can only push a single NDP to the end. Return
+		 * NULL to send what we've already got and queue this
+		 * skb for later.
+		 */
+		else if (ctx->delayed_ndp16->dwSignature)
+			return NULL;
+	}
+
 	/* follow the chain of NDPs, looking for a match */
 	while (ndpoffset) {
 		ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);