[PATCH] net: usb: cdc_eem: fix mtu

[PATCH] net: usb: cdc_eem: fix mtu

[Rabin Vincent]

Make CDC EEM recalculate the hard_mtu after adjusting the
hard_header_len.

Without this, usbnet adjusts the MTU down to 1494 bytes, and the host is
unable to receive standard 1500-byte frames from the device.

Tested with the Linux USB Ethernet gadget.

Cc: Oliver Neukum <oliver-Q6YOFhsQ4GZ7tPAFqOLdPg@public.gmane.org>
Signed-off-by: Rabin Vincent <rabin-66gdRtMMWGc@public.gmane.org>
---
 drivers/net/usb/cdc_eem.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
index 882f53f..82d43b2 100644
--- a/drivers/net/usb/cdc_eem.c
+++ b/drivers/net/usb/cdc_eem.c
@@ -93,6 +93,7 @@ static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
 	/* no jumbogram (16K) support for now */
 
 	dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
+	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
 
 	return 0;
 }
-- 
1.7.9.1

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Re: [PATCH] net: usb: cdc_eem: fix mtu

[David Miller]

From: Rabin Vincent <rabin@rab.in>
Date: Thu, 29 Mar 2012 22:45:15 +0530

> Make CDC EEM recalculate the hard_mtu after adjusting the
> hard_header_len.
> 
> Without this, usbnet adjusts the MTU down to 1494 bytes, and the host is
> unable to receive standard 1500-byte frames from the device.
> 
> Tested with the Linux USB Ethernet gadget.
> 
> Cc: Oliver Neukum <oliver@neukum.name>
> Signed-off-by: Rabin Vincent <rabin@rab.in>

Applied and queued up for -stable, thanks.