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path: root/drivers/net/usb/cdc_ncm.c
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Diffstat (limited to 'drivers/net/usb/cdc_ncm.c')
-rw-r--r--drivers/net/usb/cdc_ncm.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index d350d2795e10..549dbac710ed 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -73,6 +73,7 @@ static int cdc_ncm_setup(struct usbnet *dev)
u8 iface_no;
int err;
int eth_hlen;
+ u16 mbim_mtu;
u16 ntb_fmt_supported;
__le16 max_datagram_size;
@@ -252,6 +253,14 @@ out:
/* set MTU to max supported by the device if necessary */
if (dev->net->mtu > ctx->max_datagram_size - eth_hlen)
dev->net->mtu = ctx->max_datagram_size - eth_hlen;
+
+ /* do not exceed operater preferred MTU */
+ if (ctx->mbim_extended_desc) {
+ mbim_mtu = le16_to_cpu(ctx->mbim_extended_desc->wMTU);
+ if (mbim_mtu != 0 && mbim_mtu < dev->net->mtu)
+ dev->net->mtu = mbim_mtu;
+ }
+
return 0;
}
@@ -390,6 +399,14 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
ctx->mbim_desc = (const struct usb_cdc_mbim_desc *)buf;
break;
+ case USB_CDC_MBIM_EXTENDED_TYPE:
+ if (buf[0] < sizeof(*(ctx->mbim_extended_desc)))
+ break;
+
+ ctx->mbim_extended_desc =
+ (const struct usb_cdc_mbim_extended_desc *)buf;
+ break;
+
default:
break;
}