Re: [PATCH v8 18/24] coresight: cti: Fix bug clearing sysfs links on callback

From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Tingwei Zhang <tingwei@codeaurora.org>
Cc: tsoni@codeaurora.org,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Kim Phillips <kim.phillips@arm.com>,
	Mao Jinlong <jinlmao@codeaurora.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	coresight@lists.linaro.org, Randy Dunlap <rdunlap@infradead.org>,
	Mian Yousaf Kaukab <ykaukab@suse.de>,
	Russell King <linux@armlinux.org.uk>,
	Leo Yan <leo.yan@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Mike Leach <mike.leach@linaro.org>
Subject: Re: [PATCH v8 18/24] coresight: cti: Fix bug clearing sysfs links on callback
Date: Mon, 17 Aug 2020 10:21:00 -0600	[thread overview]
Message-ID: <20200817162100.GC3614061@xps15> (raw)
In-Reply-To: <20200807111153.7784-19-tingwei@codeaurora.org>

On Fri, Aug 07, 2020 at 07:11:47PM +0800, Tingwei Zhang wrote:
> From: Mike Leach <mike.leach@linaro.org>
> 
> During module unload, a coresight driver module will call back into
> the CTI driver to remove any links between the two devices.
> 
> The current code has 2 issues:-
> 1) in the CTI driver the matching code is matching to the wrong device
> so misses all the links.
> 2) The callback is called too late in the unload process resulting in a
> crash.
> 
> This fixes both the issues.

This patch may no longer be required if my recommendation from patch 16 is
followed.

> 
> Fixes: 177af8285b59 (coresight: cti: Enable CTI associated with devices)

Same comment as in my previous patch, we need a set of double quotes for the
title.

> Reported-by: Tingwei Zhang <tingwei@codeaurora.org>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
>  drivers/hwtracing/coresight/coresight-cti.c | 2 +-
>  drivers/hwtracing/coresight/coresight.c     | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> index 1c34db7d1b1b..6bb06c5715db 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -608,7 +608,7 @@ void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
>  		ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
>  		ctidev = &ctidrv->ctidev;
>  		list_for_each_entry(tc, &ctidev->trig_cons, node) {
> -			if (tc->con_dev == csdev->ect_dev) {
> +			if (tc->con_dev == csdev) {
>  				cti_remove_sysfs_link(ctidrv, tc);
>  				tc->con_dev = NULL;
>  				break;
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 31b9ec8d3b9c..d066411aa794 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -1256,8 +1256,6 @@ static void coresight_device_release(struct device *dev)
>  {
>  	struct coresight_device *csdev = to_coresight_device(dev);
>  
> -	if (cti_assoc_ops && cti_assoc_ops->remove)
> -		cti_assoc_ops->remove(csdev);
>  	fwnode_handle_put(csdev->dev.fwnode);
>  	kfree(csdev->refcnt);
>  	kfree(csdev);
> @@ -1592,6 +1590,8 @@ void coresight_unregister(struct coresight_device *csdev)
>  {
>  	etm_perf_del_symlink_sink(csdev);
>  	/* Remove references of that device in the topology */
> +	if (cti_assoc_ops && cti_assoc_ops->remove)
> +		cti_assoc_ops->remove(csdev);
>  	coresight_remove_conns(csdev);
>  	coresight_clear_default_sink(csdev);
>  	coresight_release_platform_data(csdev, csdev->pdata);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

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