diff options
| author |   Bjørn Mork <bjorn@mork.no> | 2015-12-23 13:42:43 +0100 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2015-12-23 22:52:08 -0500 |
| commit | 1dfddff5fcd869fcab0c52fafae099dfa435a935 (patch) | |
| tree | b0c5d35d7cd42c16f8364f4028a9313cc1eb6666 /include/linux/usb/cdc_ncm.h | |
| parent | geneve: initialize needed_headroom (diff) | |
| download | linux-dev-1dfddff5fcd869fcab0c52fafae099dfa435a935.tar.xz linux-dev-1dfddff5fcd869fcab0c52fafae099dfa435a935.zip | |
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 'include/linux/usb/cdc_ncm.h')
| -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); |