linux-kernel - Re: [PATCH v10 18/24] coresight: cti: Fix bug clearing sysfs links on callback

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Message-ID: <20200910230043.GD590446@xps15>
Date:   Thu, 10 Sep 2020 17:00:43 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Tingwei Zhang <tingwei@...eaurora.org>
Cc:     Suzuki K Poulose <suzuki.poulose@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Mike Leach <mike.leach@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Leo Yan <leo.yan@...aro.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Russell King <linux@...linux.org.uk>,
        Kim Phillips <kim.phillips@....com>,
        Mian Yousaf Kaukab <ykaukab@...e.de>, tsoni@...eaurora.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Mao Jinlong <jinlmao@...eaurora.org>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 18/24] coresight: cti: Fix bug clearing sysfs links
 on callback

On Fri, Aug 21, 2020 at 11:44:39AM +0800, Tingwei Zhang wrote:
> From: Mike Leach <mike.leach@...aro.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.
> 
> Fixes: 177af8285b59 ("coresight: cti: Enable CTI associated with devices")
> Reported-by: Tingwei Zhang <tingwei@...eaurora.org>
> Signed-off-by: Mike Leach <mike.leach@...aro.org>
> Signed-off-by: Tingwei Zhang <tingwei@...eaurora.org>
> Acked-by: Suzuki K Poulose <suzuki.poulose@....com>

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

> ---
>  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 73304374a155..ec286d617b73 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -608,7 +608,7 @@ static 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 c2174fed263b..6c09be15d60c 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -1254,8 +1254,6 @@ 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);
> @@ -1590,6 +1588,8 @@ 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
>