diff options
| author | Bjørn Mork <bjorn@mork.no> | 2015-12-23 13:42:43 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-31 11:25:49 -0800 |
| commit | 195ef86c93aa5435db588f55ad6e78d5193f072f (patch) | |
| tree | 43d02f4e13d4bf30dc7355f8bfa603828cab4418 /include/linux | |
| parent | cc72662587e40a6907326b9000182a6b6b166c43 (diff) | |
net: cdc_ncm: avoid changing RX/TX buffers on MTU changes
[ Upstream commit 1dfddff5fcd869fcab0c52fafae099dfa435a935 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/usb/cdc_ncm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 1f6526c76ee8..3a375d07d0dc 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -138,6 +138,7 @@ struct cdc_ncm_ctx { }; u8 cdc_ncm_select_altsetting(struct usb_interface *intf); +int cdc_ncm_change_mtu(struct net_device *net, int new_mtu); int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags); void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf); struct sk_buff *cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign); |