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

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Message-ID: <ed621d62-a1d2-abe1-3763-60ea6e5f615f@arm.com>
Date:   Fri, 20 Jul 2018 09:43:06 +0100
From:   Suzuki K Poulose <Suzuki.Poulose@....com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
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 19/07/18 21:07, Mathieu Poirier wrote:
> 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.

Actually, we do have the PER_CPU variables in the file already, which is why I left
them there.  See the next line.
> 
>>   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.

Sure