linux-kernel - Re: [PATCH v3 2/2] coresight: core: Disable helpers for devices that fail to enable

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Message-ID: <358f4a8c-29ad-4e5e-91b9-063f06e769ec@linaro.org>
Date: Tue, 15 Apr 2025 14:51:39 +0100
From: James Clark <james.clark@...aro.org>
To: Yabin Cui <yabinc@...gle.com>
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, Suzuki K Poulose <suzuki.poulose@....com>,
 Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@....com>,
 Jie Gan <quic_jiegan@...cinc.com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Subject: Re: [PATCH v3 2/2] coresight: core: Disable helpers for devices that
 fail to enable



On 08/04/2025 8:59 pm, Yabin Cui wrote:
> When enabling a SINK or LINK type coresight device fails, the
> associated helpers should be disabled.
> 
> Signed-off-by: Yabin Cui <yabinc@...gle.com>
> Suggested-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>   drivers/hwtracing/coresight/coresight-core.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index fb43ef6a3b1f..a56ba9087538 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -486,8 +486,10 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode,
>   			 * that need disabling. Disabling the path here
>   			 * would mean we could disrupt an existing session.
>   			 */
> -			if (ret)
> +			if (ret) {
> +				coresight_disable_helpers(csdev);

Hi Yabin,

Unfortunately coresight_disable_helpers() takes a path pointer now so 
this needs to be updated.

I tested with that change made and it works ok.

>   				goto out;
> +			}
>   			break;
>   		case CORESIGHT_DEV_TYPE_SOURCE:
>   			/* sources are enabled from either sysFS or Perf */
> @@ -496,10 +498,13 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode,
>   			parent = list_prev_entry(nd, link)->csdev;
>   			child = list_next_entry(nd, link)->csdev;
>   			ret = coresight_enable_link(csdev, parent, child, source);
> -			if (ret)
> +			if (ret) {
> +				coresight_disable_helpers(csdev);
>   				goto err;
> +			}
>   			break;
>   		default:
> +			coresight_disable_helpers(csdev);

Minor nit, you could collapse these last two into "goto 
err_disable_helpers" and add another label before err: that disables 
helpers before falling through to err:.

Other than that:

Reviewed-by: James Clark <james.clark@...aro.org>

>   			goto err;
>   		}
>   	}