From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756691Ab2IQOxk (ORCPT ); Mon, 17 Sep 2012 10:53:40 -0400 Received: from g6t0185.atlanta.hp.com ([15.193.32.62]:34657 "EHLO g6t0185.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756410Ab2IQOxi (ORCPT ); Mon, 17 Sep 2012 10:53:38 -0400 X-Greylist: delayed 454 seconds by postgrey-1.27 at vger.kernel.org; Mon, 17 Sep 2012 10:53:38 EDT Message-ID: <1347893158.3227.15.camel@lorien2> Subject: Re: [PATCH] dma-debug: New interfaces to debug dma mapping errors From: Shuah Khan Reply-To: shuah.khan@hp.com To: Greg KH Cc: konrad.wilk@oracle.com, joerg.roedel@amd.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, rob@landley.net, akpm@linux-foundation.org, bhelgaas@google.com, stern@rowland.harvard.edu, devel@linuxdriverproject.org, x86@kernel.org, LKML , linux-doc@vger.kernel.org, shuahkhan@gmail.com Date: Mon, 17 Sep 2012 08:45:58 -0600 In-Reply-To: <20120917020741.GA3841@kroah.com> References: <1347843171.4370.13.camel@lorien2> <20120917020741.GA3841@kroah.com> Organization: ISS-Linux Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2012-09-16 at 19:07 -0700, Greg KH wrote: > On Sun, Sep 16, 2012 at 06:52:51PM -0600, Shuah Khan wrote: > > +void debug_dma_dump_map_errors(struct device *dev, int all) > > +{ > > + if (all) { > > + dev_info(dev, > > + "DMA-API: DMA map error summary:\n" > > + "DMA map errors returned = %d\n" > > + "DMA map errors not checked = %d\n" > > + "DMA unmap errors = %d\n" > > + "SWIOTLB overflow triggers = %d\n", > > + dev->dma_map_errors, > > + dev->dma_map_errors_not_checked, > > + dev->dma_unmap_errors, > > + dev->iotlb_overflow_cnt); > > + return; > > + } > > + > > + if (dev->dma_map_errors_not_checked) { > > + dev_err(dev, > > + "DMA-API: Driver failed to check\n" > > + "%d out of a total of %d DMA map errors returned\n" > > + "by DMA mapping interfaces\n", > > + dev->dma_map_errors_not_checked, > > + dev->dma_map_errors); > > + } > > + > > + if (dev->dma_unmap_errors) { > > + dev_err(dev, > > + "DMA-API: Driver tried to free invalid\n" > > + "DMA addresses %d times\n", > > + dev->dma_unmap_errors); > > + } > > + > > + if (dev->iotlb_overflow_cnt) { > > + dev_err(dev, > > + "DMA-API: SWIOTLB overflow buffer triggered %d times\n", > > + dev->iotlb_overflow_cnt); > > + } > > +} > > +EXPORT_SYMBOL(debug_dma_dump_map_errors); > > Don't use syslog for stuff like this, that's not good. Why not use > debugfs? This debug interface debug_dma_dump_map_errors() is enabled only when CONFIG_DMA_API_DEBUG is enabled, however I agree that debugfs is a better choice than logging to syslog. I created debugfs interfaces for these error counts at system level. Are recommending the same approach for per device counts as well? -- Shuah