linux-kernel - Re: [PATCH v2 08/10] coresight: perf: Add helper to retrieve sink configuration

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Date:   Thu, 19 Jul 2018 14:07:39 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        robert.walker@....com, mike.leach@...aro.org,
        coresight@...ts.linaro.org
Subject: Re: [PATCH v2 08/10] coresight: perf: Add helper to retrieve sink
 configuration

On Tue, Jul 17, 2018 at 06:11:39PM +0100, Suzuki K Poulose wrote:
> We can always find the sink configuration for a given perf_output_handle.
> Add a helper to retrieve the sink configuration for a given
> perf_output_handle. This will be used to get rid of the set_buffer()
> call back.
> 
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>  drivers/hwtracing/coresight/coresight-etm-perf.c | 14 -------------
>  drivers/hwtracing/coresight/coresight-etm-perf.h | 26 ++++++++++++++++++++++++
>  2 files changed, 26 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 6a4252b..3cc4a0b 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -23,20 +23,6 @@
>  static struct pmu etm_pmu;
>  static bool etm_perf_up;
>  
> -/**
> - * struct etm_event_data - Coresight specifics associated to an event
> - * @work:		Handle to free allocated memory outside IRQ context.
> - * @mask:		Hold the CPU(s) this event was set for.
> - * @snk_config:		The sink configuration.
> - * @path:		An array of path, each slot for one CPU.
> - */
> -struct etm_event_data {
> -	struct work_struct work;
> -	cpumask_t mask;
> -	void *snk_config;
> -	struct list_head * __percpu *path;
> -};
> -

If this is moved to coresight-etm-perf.h, the #include <linux/percpu-defs.h> can
be removed.

>  static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
>  static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
>  
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
> index 4197df4..da7d933 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.h
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
> @@ -7,6 +7,7 @@
>  #ifndef _CORESIGHT_ETM_PERF_H
>  #define _CORESIGHT_ETM_PERF_H
>  
> +#include <linux/percpu-defs.h>
>  #include "coresight-priv.h"
>  
>  struct coresight_device;
> @@ -42,14 +43,39 @@ struct etm_filters {
>  	bool			ssstatus;
>  };
>  
> +/**
> + * struct etm_event_data - Coresight specifics associated to an event
> + * @work:		Handle to free allocated memory outside IRQ context.
> + * @mask:		Hold the CPU(s) this event was set for.
> + * @snk_config:		The sink configuration.
> + * @path:		An array of path, each slot for one CPU.
> + */
> +struct etm_event_data {
> +	struct work_struct work;
> +	cpumask_t mask;
> +	void *snk_config;
> +	struct list_head * __percpu *path;
> +};
>  
>  #ifdef CONFIG_CORESIGHT
>  int etm_perf_symlink(struct coresight_device *csdev, bool link);
> +static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
> +{
> +	struct etm_event_data *data = perf_get_aux(handle);
>  
> +	if (data)
> +		return data->snk_config;
> +	return NULL;
> +}
>  #else
>  static inline int etm_perf_symlink(struct coresight_device *csdev, bool link)
>  { return -EINVAL; }
>  
> +static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
> +{
> +	return NULL;
> +}
> +

I think we can do without those... See my comment in the next patch.

Thanks,
Mathieu

>  #endif /* CONFIG_CORESIGHT */
>  
>  #endif
> -- 
> 2.7.4
>