From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] jme: Fix DMA unmap warning Date: Wed, 07 May 2014 16:44:34 -0400 (EDT) Message-ID: <20140507.164434.997979341700998470.davem@davemloft.net> References: <1399315907-27148-1-git-send-email-nhorman@tuxdriver.com> <20140507.155613.630399521517455317.davem@davemloft.net> <20140507203317.GC8786@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, cooldavid@cooldavid.org To: nhorman@tuxdriver.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:51728 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100AbaEGUoi (ORCPT ); Wed, 7 May 2014 16:44:38 -0400 In-Reply-To: <20140507203317.GC8786@hmsreliant.think-freely.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Neil Horman Date: Wed, 7 May 2014 16:33:17 -0400 > Perhaps a solution is a signalling mechanism tied to completion interrupts? > I.e. a mapping failure gets reported to the stack, which causes the > correspondnig queue to be stopped, until such time a the driver signals a safe > restart by the reception of a tx completion interrupt? I'm actually tinkering > right now with a mechanism that provides guidance to the stack as to how many > dma descriptors are available in a given net_device that might come in handy > here Another idea is to signal it from the IOMMU unmap itself, since that is the point where the resource becomes available. Actually either approach is fine with me.