On Mon, 16 Mar 2015, Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx> wrote:
> So that the compiler warns if we get something wrong.
>
> Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 39 ++++++++++++++++++++++++++-------------
> 1 file changed, 26 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index ae4ba6a..871d77a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -232,30 +232,43 @@ enum hpd_pin {
> (__s) < INTEL_INFO(__dev_priv)->num_sprites[(__p)]; \
> (__s)++)
>
> -#define for_each_crtc(dev, crtc) \
> +#define type_check(variable, type) \
> + { \
> + typeof(variable) __dummy_ptr = NULL; \
> + const type *__type_check = __dummy_ptr; \
> + (void) __type_check; \
> + }
> +
> +#define for_each_crtc(dev, crtc) \
> + type_check(crtc, struct drm_crtc) \
> list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
if (foo)
for_each_crtc(dev, crtc);
will do type_check if foo, but list_for_each_entry unconditionally.
I think this is too fragile.
I'm already pretty anxious about our loop macros with an if in them
blowing up due to the dangling else:
if (foo)
list_for_each_encoder_on_crtc(dev, crtc, intel_encoder)
bar();
else
baz();
where baz() gets called for each encoder *not* on crtc, instead of once
for !foo.
BR,
Jani.
>
> -#define for_each_intel_crtc(dev, intel_crtc) \
> - list_for_each_entry(intel_crtc, &dev->mode_config.crtc_list, base.head)
> +#define for_each_intel_crtc(dev, crtc) \
> + type_check(crtc, struct intel_crtc) \
> + list_for_each_entry(crtc, &dev->mode_config.crtc_list, base.head)
>
> -#define for_each_intel_encoder(dev, intel_encoder) \
> - list_for_each_entry(intel_encoder, \
> +#define for_each_intel_encoder(dev, encoder) \
> + type_check(encoder, struct intel_encoder) \
> + list_for_each_entry(encoder, \
> &(dev)->mode_config.encoder_list, \
> base.head)
>
> -#define for_each_intel_connector(dev, intel_connector) \
> - list_for_each_entry(intel_connector, \
> +#define for_each_intel_connector(dev, connector) \
> + type_check(connector, struct intel_connector); \
> + list_for_each_entry(connector, \
> &dev->mode_config.connector_list, \
> base.head)
>
>
> -#define for_each_encoder_on_crtc(dev, __crtc, intel_encoder) \
> - list_for_each_entry((intel_encoder), &(dev)->mode_config.encoder_list, base.head) \
> - if ((intel_encoder)->base.crtc == (__crtc))
> +#define for_each_encoder_on_crtc(dev, __crtc, encoder) \
> + type_check(encoder, struct intel_encoder) \
> + list_for_each_entry((encoder), &(dev)->mode_config.encoder_list, base.head) \
> + if ((encoder)->base.crtc == (__crtc))
>
> -#define for_each_connector_on_encoder(dev, __encoder, intel_connector) \
> - list_for_each_entry((intel_connector), &(dev)->mode_config.connector_list, base.head) \
> - if ((intel_connector)->base.encoder == (__encoder))
> +#define for_each_connector_on_encoder(dev, __encoder, connector) \
> + type_check(connector, struct intel_connector) \
> + list_for_each_entry((connector), &(dev)->mode_config.connector_list, base.head) \
> + if ((connector)->base.encoder == (__encoder))
>
> #define for_each_power_domain(domain, mask) \
> for ((domain) = 0; (domain) < POWER_DOMAIN_NUM; (domain)++) \
> --
> 2.1.0
>
> _______________________________________________
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> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Jani Nikula, Intel Open Source Technology Center
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