Hello. On 5/7/2015 12:49 PM, Ruslan Bilovol wrote:
Current usbnet driver rejects setting MTU that is a multiple of USB endpoint's wMaxPacketSize size. However, it may only lead to possible performance degradation but is not so critical that its using should be prohibited. So allow it but also warn user about possible issue.
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx> --- drivers/net/usb/usbnet.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 733f4fe..09dc848 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -382,9 +382,11 @@ int usbnet_change_mtu (struct net_device *net, int new_mtu) if (new_mtu <= 0) return -EINVAL; - // no second zero-length packet read wanted after mtu-sized packets + /* warn about second zero-length packet read after mtu-sized packets */ if ((ll_mtu % dev->maxpacket) == 0) - return -EDOM; + netdev_warn(dev->net, "MTU %d is a multiple of USB wMaxPacketSize (%d)," + " consider possible performance degradation\n",
Please do not wrap the kernel messages, it impedes grepping for them. scripts/checkpatch.pl is aware of this rule.
WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
