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authorBjørn Mork <bjorn@mork.no>2015-12-23 15:42:43 +0300
committerDavid S. Miller <davem@davemloft.net>2015-12-24 06:52:08 +0300
commit1dfddff5fcd869fcab0c52fafae099dfa435a935 (patch)
treeb0c5d35d7cd42c16f8364f4028a9313cc1eb6666 /drivers/net/usb/cdc_mbim.c
parent184fc8b5ee601cd83dbbdf3e6cfec5f5b8d3b41a (diff)
downloadlinux-1dfddff5fcd869fcab0c52fafae099dfa435a935.tar.xz
net: cdc_ncm: avoid changing RX/TX buffers on MTU changes
NCM buffer sizes are negotiated with the device independently of the network device MTU. The RX buffers are allocated by the usbnet framework based on the rx_urb_size value set by cdc_ncm. A single RX buffer can hold a number of MTU sized packets. The default usbnet change_mtu ndo only modifies rx_urb_size if it is equal to hard_mtu. And the cdc_ncm driver will set rx_urb_size and hard_mtu independently of each other, based on dwNtbInMaxSize and dwNtbOutMaxSize respectively. It was therefore assumed that usbnet_change_mtu() would never touch rx_urb_size. This failed to consider the case where dwNtbInMaxSize and dwNtbOutMaxSize happens to be equal. Fix by implementing an NCM specific change_mtu ndo, modifying the netdev MTU without touching the buffer size settings. Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/usb/cdc_mbim.c')
-rw-r--r--drivers/net/usb/cdc_mbim.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index 8973abdec9f6..bdd83d95ec0a 100644
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -100,7 +100,7 @@ static const struct net_device_ops cdc_mbim_netdev_ops = {
.ndo_stop = usbnet_stop,
.ndo_start_xmit = usbnet_start_xmit,
.ndo_tx_timeout = usbnet_tx_timeout,
- .ndo_change_mtu = usbnet_change_mtu,
+ .ndo_change_mtu = cdc_ncm_change_mtu,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
.ndo_vlan_rx_add_vid = cdc_mbim_rx_add_vid,