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From: Daniel Axtens <dja@axtens•net>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: netdev@vger•kernel.org, tlfalcon@linux•vnet.ibm.com,
	Yuval.Mintz@cavium•com, ariel.elior@cavium•com,
	everest-linux-l2@cavium•com, jay.vosburgh@canonical•com
Subject: Re: [PATCH] bnx2x: drop packets where gso_size is too big for hardware
Date: Fri, 01 Sep 2017 12:42:41 +1000	[thread overview]
Message-ID: <87a82f3zry.fsf@linkitivity.dja.id.au> (raw)
In-Reply-To: <1504159341.15310.6.camel@edumazet-glaptop3.roam.corp.google.com>

Eric Dumazet <eric.dumazet@gmail•com> writes:

> If you had this test in bnx2x_features_check(), packet could be
> segmented by core networking stack before reaching bnx2x_start_xmit() by
> clearing NETIF_F_GSO_MASK
>
> -> No drop would be involved.

Thanks for the pointer - networking code is all a bit new to me.

I'm just struggling at the moment to figure out what the right way to
calculate the length. My original patch uses gso_size + hlen, but:

 - On reflection, while this solves the immediate bug, I'm not 100% sure
   this is the right thing to be calculating

 - If it is, then we have the problem that hlen is calculated in a bunch
   of weird and wonderful ways which make it a nightmare to extract.

Yuval (or anyone else who groks the driver properly) - what's the right
test to be doing here to make sure we don't write to much data to the
card?

Regards,
Daniel

next prev parent reply	other threads:[~2017-09-01  2:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31  5:46 [PATCH] bnx2x: drop packets where gso_size is too big for hardware Daniel Axtens
2017-08-31  6:02 ` Eric Dumazet
2017-09-01  2:42   ` Daniel Axtens [this message]
2017-09-18  4:41   ` Daniel Axtens
2017-09-18 14:42     ` Eric Dumazet

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