[Intel-gfx] [PATCH] drm/i915: Add i915_param charp macro magic

[Jani Nikula]

On Tue, 21 Feb 2017, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Handling the dynamic charp module parameter requires us to copy it for
> the error state, or remember to lock it when reading (in case it used
> with 0600).
>
> v2: Use __always_inline and __builtin_strcmp
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula at intel.com>

> ---
>  drivers/gpu/drm/i915/i915_debugfs.c   |  2 ++
>  drivers/gpu/drm/i915/i915_gpu_error.c | 22 ++++++++++++++++++++++
>  2 files changed, 24 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 768461f7c7c6..655e60d609c2 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -72,6 +72,8 @@ static __always_inline void seq_print_param(struct seq_file *m,
>  		seq_printf(m, "i915.%s=%d\n", name, *(const int *)x);
>  	else if (!__builtin_strcmp(type, "unsigned int"))
>  		seq_printf(m, "i915.%s=%u\n", name, *(const unsigned int *)x);
> +	else if (!__builtin_strcmp(type, "char *"))
> +		seq_printf(m, "i915.%s=%s\n", name, *(const char **)x);
>  	else
>  		BUILD_BUG();
>  }
> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> index 3a3c7c3c4931..2b1d15668192 100644
> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> @@ -557,6 +557,8 @@ static __always_inline void err_print_param(struct drm_i915_error_state_buf *m,
>  		err_printf(m, "i915.%s=%d\n", name, *(const int *)x);
>  	else if (!__builtin_strcmp(type, "unsigned int"))
>  		err_printf(m, "i915.%s=%u\n", name, *(const unsigned int *)x);
> +	else if (!__builtin_strcmp(type, "char *"))
> +		err_printf(m, "i915.%s=%s\n", name, *(const char **)x);
>  	else
>  		BUILD_BUG();
>  }
> @@ -810,6 +812,12 @@ static void i915_error_object_free(struct drm_i915_error_object *obj)
>  	kfree(obj);
>  }
>  
> +static __always_inline void free_param(const char *type, void *x)
> +{
> +	if (!__builtin_strcmp(type, "char *"))
> +		kfree(*(void **)x);
> +}
> +
>  void __i915_gpu_state_free(struct kref *error_ref)
>  {
>  	struct i915_gpu_state *error =
> @@ -840,6 +848,11 @@ void __i915_gpu_state_free(struct kref *error_ref)
>  
>  	kfree(error->overlay);
>  	kfree(error->display);
> +
> +#define FREE(T, x) free_param(#T, &error->params.x);
> +	I915_PARAMS_FOR_EACH(FREE);
> +#undef FREE
> +
>  	kfree(error);
>  }
>  
> @@ -1614,6 +1627,12 @@ static void i915_capture_gen_state(struct drm_i915_private *dev_priv,
>  	       sizeof(error->device_info));
>  }
>  
> +static __always_inline void dup_param(const char *type, void *x)
> +{
> +	if (!__builtin_strcmp(type, "char *"))
> +		*(void **)x = kstrdup(*(void **)x, GFP_ATOMIC);
> +}
> +
>  static int capture(void *data)
>  {
>  	struct i915_gpu_state *error = data;
> @@ -1625,6 +1644,9 @@ static int capture(void *data)
>  					   error->i915->gt.last_init_time));
>  
>  	error->params = i915;
> +#define DUP(T, x) dup_param(#T, &error->params.x);
> +	I915_PARAMS_FOR_EACH(DUP);
> +#undef DUP
>  
>  	i915_capture_gen_state(error->i915, error);
>  	i915_capture_reg_state(error->i915, error);

-- 
Jani Nikula, Intel Open Source Technology Center