Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751480AbdFEKKk (ORCPT ); Mon, 5 Jun 2017 06:10:40 -0400 Received: from mail-pf0-f175.google.com ([209.85.192.175]:34751 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751320AbdFEKKj (ORCPT ); Mon, 5 Jun 2017 06:10:39 -0400 Date: Mon, 5 Jun 2017 18:10:30 +0800 From: Leo Yan To: Suzuki K Poulose Cc: Mathieu Poirier , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mike Leach , Chunyan Zhang Subject: Re: [PATCH v1 2/4] coresight: add and remove panic callback for sink Message-ID: <20170605101029.GC8682@leoy-ThinkPad-T440> References: <1496500976-18362-1-git-send-email-leo.yan@linaro.org> <1496500976-18362-3-git-send-email-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 52 On Mon, Jun 05, 2017 at 10:24:41AM +0100, Suzuki K Poulose wrote: > On 03/06/17 15:42, Leo Yan wrote: > >If the sink device has panic callback function, add the panic callback > >node for coresight panic dump list when the sink device is enabled; > >also cleanup the node when the sink device is disabled. > > > >Signed-off-by: Leo Yan > >--- > > drivers/hwtracing/coresight/coresight.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > >diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c > >index 0c37356..5928886 100644 > >--- a/drivers/hwtracing/coresight/coresight.c > >+++ b/drivers/hwtracing/coresight/coresight.c > >@@ -138,6 +138,13 @@ static int coresight_enable_sink(struct coresight_device *csdev, u32 mode) > > if (ret) > > return ret; > > } > >+ > >+ /* Add kernel panic callback */ > >+ if (sink_ops(csdev)->panic_cb) { > >+ ret = coresight_add_panic_cb(csdev); > >+ if (ret) > >+ return ret; > >+ } > > csdev->enable = true; > > } > > > >@@ -149,6 +156,10 @@ static int coresight_enable_sink(struct coresight_device *csdev, u32 mode) > > static void coresight_disable_sink(struct coresight_device *csdev) > > { > > if (atomic_dec_return(csdev->refcnt) == 0) { > >+ /* Remove kernel panic callback */ > >+ if (sink_ops(csdev)->panic_cb) > >+ coresight_del_panic_cb(csdev); > >+ > > if (sink_ops(csdev)->disable) { > > sink_ops(csdev)->disable(csdev); > > csdev->enable = false; > > > > Just a thought, instead of adding/deleting every time the sink is enabled, > could we add/del the device once for-ever and let the panic_cb decide to dump > it based on whether the device was active or not ? Yeah, we can check 'if (drvdata->mode == CS_MODE_DISABLED)' and directly bail out if the module is disabled for panic dumping. Will fix with this way. Thanks, Leo Yan