linux-kernel - Re: [PATCH 2/2] coresight: trbe: Allocate platform data per device

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Message-ID: <9cd9f83c-7778-2d87-a175-a4cb7ceb8723@arm.com>
Date:   Thu, 17 Aug 2023 12:07:02 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Suzuki K Poulose <suzuki.poulose@....com>, hejunhao3@...wei.com
Cc:     coresight@...ts.linaro.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, jonathan.cameron@...wei.com,
        leo.yan@...aro.org, mike.leach@...aro.org, james.clark@....com,
        linuxarm@...wei.com, yangyicong@...wei.com,
        prime.zeng@...ilicon.com
Subject: Re: [PATCH 2/2] coresight: trbe: Allocate platform data per device

Hi Suzuki,

Seems like this patch is going to conflict with the below proposed change

https://lore.kernel.org/all/20230817055405.249630-4-anshuman.khandual@arm.com/

Please let me know how should we resolve this conflict.

On 8/16/23 19:40, Suzuki K Poulose wrote:
> Coresight TRBE driver shares a single platform data (which is empty btw).
> However, with the commit 4e8fe7e5c3a5
> ("coresight: Store pointers to connections rather than an array of them")
> the coresight core would free up the pdata, resulting in multiple attempts
> to free the same pdata for TRBE instances. Fix this by allocating a pdata per
> coresight_device.
> 
> Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")

The above mentioned commit i.e 4e8fe7e5c3a5 seems to be a more recent one which
has triggered this problem. But would the problem be still there without that ?
Else 'Fixes:' tag would need changing.

> Link: https://lore.kernel.org/r/20230814093813.19152-3-hejunhao3@huawei.com
> Reported-by: Junhao He <hejunhao3@...wei.com>
> Cc: Anshuman Khandual <anshuman.khandual@....com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>  drivers/hwtracing/coresight/coresight-trbe.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> index 025f70adee47..d3d34a833f01 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -1255,10 +1255,13 @@ static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cp
>  	if (!desc.name)
>  		goto cpu_clear;
>  
> +	desc.pdata = coresight_get_platform_data(dev);
> +	if (IS_ERR(desc.pdata))
> +		goto cpu_clear;
> +
>  	desc.type = CORESIGHT_DEV_TYPE_SINK;
>  	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM;
>  	desc.ops = &arm_trbe_cs_ops;
> -	desc.pdata = dev_get_platdata(dev);
>  	desc.groups = arm_trbe_groups;
>  	desc.dev = dev;
>  	trbe_csdev = coresight_register(&desc);
> @@ -1482,7 +1485,6 @@ static void arm_trbe_remove_irq(struct trbe_drvdata *drvdata)
>  
>  static int arm_trbe_device_probe(struct platform_device *pdev)
>  {
> -	struct coresight_platform_data *pdata;
>  	struct trbe_drvdata *drvdata;
>  	struct device *dev = &pdev->dev;
>  	int ret;
> @@ -1497,12 +1499,7 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
>  	if (!drvdata)
>  		return -ENOMEM;
>  
> -	pdata = coresight_get_platform_data(dev);
> -	if (IS_ERR(pdata))
> -		return PTR_ERR(pdata);
> -
>  	dev_set_drvdata(dev, drvdata);
> -	dev->platform_data = pdata;
>  	drvdata->pdev = pdev;
>  	ret = arm_trbe_probe_irq(pdev, drvdata);
>  	if (ret)