[dpdk-dev] [PATCH v2] nfp: handle packets with length 0 as usual ones

[Ferruh Yigit]

On 8/22/2017 11:41 AM, Alejandro Lucero wrote:
> A DPDK app could, whatever the reason, send packets with size 0.
> The PMD is not sending those packets, which does make sense,
> but the problem is the mbuf is not released either. That leads
> to mbufs not being available, because the app trusts the
> PMD will do it.
> 
> Although this is a problem related to app wrong behaviour, we
> should harden the PMD in this regard. Not sending a packet with
> size 0 could be problematic, needing special handling inside the
> PMD xmit function. It could be a burst of those packets, which can
> be easily handled, but it could also be a single packet in a burst,
> what is harder to handle.
> 
> It would be simpler to just send that kind of packets, which will
> likely be dropped by the hw at some point. The main problem is how
> the fw/hw handles the DMA, because a dma read to a hypothetical 0x0
> address could trigger an IOMMU error. It turns out, it is safe to
> send a descriptor with packet size 0 to the hardware: the DMA never
> happens, from the PCIe point of view.

> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>

Applied to dpdk-next-net/master, thanks.