From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net] r8152: drop the tx packet with invalid length
Date: Wed, 26 Nov 2014 15:33:56 -0500 (EST)
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Cc: hayeswang@realtek.com, netdev@vger.kernel.org,
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 26 Nov 2014 10:44:19 -0800

> On Wed, 2014-11-26 at 12:06 -0500, David Miller wrote:
>> From: Eric Dumazet <eric.dumazet@gmail.com>
>> Date: Wed, 26 Nov 2014 08:52:28 -0800
>> 
>> > On Wed, 2014-11-26 at 17:56 +0800, Hayes Wang wrote:
>> >> Drop the tx packet which is more than the size of agg_buf_sz. When
>> >> creating a bridge with the device, we may get the tx packet with
>> >> TSO and the length is more than the gso_max_size which is set by
>> >> the driver through netif_set_gso_max_size(). Such packets couldn't
>> >> be transmitted and should be dropped directly.
>> >> 
>> >> Signed-off-by: Hayes Wang <hayeswang@realtek.com>
>>  ...
>> > Looks like a candidate for ndo_gso_check(), so that we do not drop, but
>> > instead segment from netif_needs_gso()/validate_xmit_skb()
>> 
>> You mean have the bridge implement the ndo_gso_check() method right?
> 
> No, I meant this particular driver.
> 
> Note that netif_skb_features() does only this check :
> 
> if (gso_segs > dev->gso_max_segs || gso_segs < dev->gso_min_segs)
>       features &= ~NETIF_F_GSO_MASK;
> 
> Ie not testing gso_max_size
> 
> It looks like all these particular tests should be moved on
> ndo_gso_check(), to remove code from netif_skb_features()

A check against gso_max_size is generic enough that it ought to be put
right into netif_needs_gso() rather then duplicating it into every
driver's ndo_gso_check() method don't you think?