netdev - Re: [PATCH] vmxnet3: prevent receive getting out of sequence on napi poll

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Date:	Tue, 7 Jul 2015 14:10:50 -0400
From:	Andy Gospodarek <gospo@...ulusnetworks.com>
To:	Neil Horman <nhorman@...driver.com>
Cc:	netdev@...r.kernel.org, Shreyas Bhatewara <sbhatewara@...are.com>,
	"David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH] vmxnet3: prevent receive getting out of sequence on napi
 poll

On Tue, Jul 07, 2015 at 02:02:18PM -0400, Neil Horman wrote:
> vmxnet3's current napi path is built to count every rx descriptor we recieve,
> and use that as a count of the napi budget.  That means its possible to return
> from a napi poll halfway through recieving a fragmented packet accross multiple
> dma descriptors.  If that happens, the next napi poll will start with the
> descriptor ring in an improper state (e.g. the first descriptor we look at may
> have the end-of-packet bit set), which will cause a BUG halt in the driver.
> 
> Fix the issue by only counting whole received packets in the napi poll and
> returning that value, rather than the descriptor count.
> 
> Tested by the reporter and myself, successfully
> 
> Signed-off-by: Neil Horman <nhorman@...driver.com>
> CC: Shreyas Bhatewara <sbhatewara@...are.com>
> CC: "David S. Miller" <davem@...emloft.net>

Looks good.  I'm now curious how widespread something like this might be
for drivers that use a similar EOP marker....

Acked-by: Andy Gospodarek <gospo@...ulusnetworks.com>
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