From: Tom Lendacky <thomas.lenda...@amd.com> Date: Wed, 21 Oct 2015 15:37:05 -0500
> The code currently uses the lightweight dma_wmb barrier before updating > the current descriptor count. Under heavy load, the Tx cleanup routine > was seeing the updated current descriptor count before the updated > descriptor information. As a result, the Tx descriptor was being cleaned > up before it was used because it was not "owned" by the hardware yet, > resulting in a Tx queue hang. > > Using the wmb barrier insures that the descriptor is updated before the > descriptor counter preventing the Tx queue hang. For extra insurance, > the Tx cleanup routine is changed to grab the current decriptor count on > entry and uses that initial value in the processing loop rather than > trying to chase the current value. > > Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> > Tested-by: Christoffer Dall <christoffer.d...@linaro.org> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
