[Intel-gfx] [PATCH v2] drm/i915/pmu: Hide the (unsigned long)ptr cast

[Tvrtko Ursulin]

On 23/11/2017 21:17, Chris Wilson wrote:
> We pretend the PMU config id is a pointer value when encoding it into
> the device parameters for presentation via sysfs. This requires casting
> of an unsigned long into and out of the pointer member, which annoys
> smatch:
> 
> drivers/gpu/drm/i915/i915_pmu.c:684 i915_pmu_event_show() warn: argument 3 to %lx specifier is cast from pointer
> 
> Instead of abusing a generic dev_ext_attribute, define our own typesafe
> attributes.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_pmu.c | 30 ++++++++++++++++++++----------
>   1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> index 6a42e7f7967d..5170a46893d7 100644
> --- a/drivers/gpu/drm/i915/i915_pmu.c
> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> @@ -650,19 +650,24 @@ static int i915_pmu_event_event_idx(struct perf_event *event)
>   	return 0;
>   }
>   
> +struct i915_str_attribute {
> +	struct device_attribute attr;
> +	const char *str;
> +};
> +
>   static ssize_t i915_pmu_format_show(struct device *dev,
>   				    struct device_attribute *attr, char *buf)
>   {
> -	struct dev_ext_attribute *eattr;
> +	struct i915_str_attribute *eattr;
>   
> -	eattr = container_of(attr, struct dev_ext_attribute, attr);
> -	return sprintf(buf, "%s\n", (char *)eattr->var);
> +	eattr = container_of(attr, struct i915_str_attribute, attr);
> +	return sprintf(buf, "%s\n", eattr->str);
>   }
>   
>   #define I915_PMU_FORMAT_ATTR(_name, _config) \
> -	(&((struct dev_ext_attribute[]) { \
> +	(&((struct i915_str_attribute[]) { \
>   		{ .attr = __ATTR(_name, 0444, i915_pmu_format_show, NULL), \
> -		  .var = (void *)_config, } \
> +		  .str = _config, } \
>   	})[0].attr.attr)
>   
>   static struct attribute *i915_pmu_format_attrs[] = {
> @@ -675,19 +680,24 @@ static const struct attribute_group i915_pmu_format_attr_group = {
>   	.attrs = i915_pmu_format_attrs,
>   };
>   
> +struct i915_ext_attribute {
> +	struct device_attribute attr;
> +	unsigned long val;
> +};
> +
>   static ssize_t i915_pmu_event_show(struct device *dev,
>   				   struct device_attribute *attr, char *buf)
>   {
> -	struct dev_ext_attribute *eattr;
> +	struct i915_ext_attribute *eattr;
>   
> -	eattr = container_of(attr, struct dev_ext_attribute, attr);
> -	return sprintf(buf, "config=0x%lx\n", (unsigned long)eattr->var);
> +	eattr = container_of(attr, struct i915_ext_attribute, attr);
> +	return sprintf(buf, "config=0x%lx\n", eattr->val);
>   }
>   
>   #define I915_EVENT_ATTR(_name, _config) \
> -	(&((struct dev_ext_attribute[]) { \
> +	(&((struct i915_ext_attribute[]) { \
>   		{ .attr = __ATTR(_name, 0444, i915_pmu_event_show, NULL), \
> -		  .var = (void *)_config, } \
> +		  .val = _config, } \
>   	})[0].attr.attr)
>   
>   #define I915_EVENT_STR(_name, _str) \
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko