From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH] jme: Fix DMA unmap warning Date: Wed, 7 May 2014 17:54:48 -0400 Message-ID: <20140507215448.GA21071@localhost.localdomain> References: <1399315907-27148-1-git-send-email-nhorman@tuxdriver.com> <20140507.155613.630399521517455317.davem@davemloft.net> <20140507203317.GC8786@hmsreliant.think-freely.org> <20140507.164434.997979341700998470.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, cooldavid@cooldavid.org To: David Miller Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:48352 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750949AbaEGVy5 (ORCPT ); Wed, 7 May 2014 17:54:57 -0400 Content-Disposition: inline In-Reply-To: <20140507.164434.997979341700998470.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, May 07, 2014 at 04:44:34PM -0400, David Miller wrote: > 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. > I'll look into it shortly. Thanks for the idea! Neil