[PATCH 2/2] drm/atomic: Make atomic iterators less surprising
Daniel Vetter
daniel at ffwll.ch
Wed Sep 27 10:14:25 UTC 2017
On Wed, Sep 27, 2017 at 10:35:32AM +0200, Maarten Lankhorst wrote:
> Commit 669c9215afea ("drm/atomic: Make async plane update checks work as
> intended, v2.") assumed incorrectly that if only 1 plane is matched in
> the loop, the variables will be set to that plane. In reality we reset
> them to NULL every time a new plane was iterated. This behavior is
> surprising, so fix this by making the for loops only assign the
> variables on a match.
Maybe explain a bit more how that's confusing, namely when we have not
added all the planes/crtc/connector to the state, and there's a few NULL
ones after the last one we iterated. Which then breaks the assumption that
the pointers will hold the values from the last loop iteration, which
holds true for all other for_each macros we're using (well except the
iterator pointer itself, but that one really is entirely internal).
With that bit of blabla added to the commit message:
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
> Cc: Dmitry Osipenko <digetx at gmail.com>
> Fixes: 669c9215afea ("drm/atomic: Make async plane update checks work as intended, v2.")
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> ---
> include/drm/drm_atomic.h | 85 ++++++++++++++++++++++++------------------------
> 1 file changed, 42 insertions(+), 43 deletions(-)
>
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index 6fae95f28e10..5afd6e364fb6 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -585,12 +585,12 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_oldnew_connector_in_state(__state, connector, old_connector_state, new_connector_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->num_connector && \
> - ((connector) = (__state)->connectors[__i].ptr, \
> - (old_connector_state) = (__state)->connectors[__i].old_state, \
> - (new_connector_state) = (__state)->connectors[__i].new_state, 1); \
> - (__i)++) \
> - for_each_if (connector)
> + (__i) < (__state)->num_connector; \
> + (__i)++) \
> + for_each_if ((__state)->connectors[__i].ptr && \
> + ((connector) = (__state)->connectors[__i].ptr, \
> + (old_connector_state) = (__state)->connectors[__i].old_state, \
> + (new_connector_state) = (__state)->connectors[__i].new_state, 1))
>
> /**
> * for_each_old_connector_in_state - iterate over all connectors in an atomic update
> @@ -606,11 +606,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_old_connector_in_state(__state, connector, old_connector_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->num_connector && \
> - ((connector) = (__state)->connectors[__i].ptr, \
> - (old_connector_state) = (__state)->connectors[__i].old_state, 1); \
> - (__i)++) \
> - for_each_if (connector)
> + (__i) < (__state)->num_connector; \
> + (__i)++) \
> + for_each_if ((__state)->connectors[__i].ptr && \
> + ((connector) = (__state)->connectors[__i].ptr, \
> + (old_connector_state) = (__state)->connectors[__i].old_state, 1))
>
> /**
> * for_each_new_connector_in_state - iterate over all connectors in an atomic update
> @@ -626,11 +626,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_new_connector_in_state(__state, connector, new_connector_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->num_connector && \
> - ((connector) = (__state)->connectors[__i].ptr, \
> - (new_connector_state) = (__state)->connectors[__i].new_state, 1); \
> - (__i)++) \
> - for_each_if (connector)
> + (__i) < (__state)->num_connector; \
> + (__i)++) \
> + for_each_if ((__state)->connectors[__i].ptr && \
> + ((connector) = (__state)->connectors[__i].ptr, \
> + (new_connector_state) = (__state)->connectors[__i].new_state, 1))
>
> /**
> * for_each_oldnew_crtc_in_state - iterate over all CRTCs in an atomic update
> @@ -646,12 +646,12 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_oldnew_crtc_in_state(__state, crtc, old_crtc_state, new_crtc_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_crtc && \
> - ((crtc) = (__state)->crtcs[__i].ptr, \
> - (old_crtc_state) = (__state)->crtcs[__i].old_state, \
> - (new_crtc_state) = (__state)->crtcs[__i].new_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_crtc; \
> (__i)++) \
> - for_each_if (crtc)
> + for_each_if ((__state)->crtcs[__i].ptr && \
> + ((crtc) = (__state)->crtcs[__i].ptr, \
> + (old_crtc_state) = (__state)->crtcs[__i].old_state, \
> + (new_crtc_state) = (__state)->crtcs[__i].new_state, 1))
>
> /**
> * for_each_old_crtc_in_state - iterate over all CRTCs in an atomic update
> @@ -666,11 +666,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_old_crtc_in_state(__state, crtc, old_crtc_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_crtc && \
> - ((crtc) = (__state)->crtcs[__i].ptr, \
> - (old_crtc_state) = (__state)->crtcs[__i].old_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_crtc; \
> (__i)++) \
> - for_each_if (crtc)
> + for_each_if ((__state)->crtcs[__i].ptr && \
> + ((crtc) = (__state)->crtcs[__i].ptr, \
> + (old_crtc_state) = (__state)->crtcs[__i].old_state, 1))
>
> /**
> * for_each_new_crtc_in_state - iterate over all CRTCs in an atomic update
> @@ -685,11 +685,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_new_crtc_in_state(__state, crtc, new_crtc_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_crtc && \
> - ((crtc) = (__state)->crtcs[__i].ptr, \
> - (new_crtc_state) = (__state)->crtcs[__i].new_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_crtc; \
> (__i)++) \
> - for_each_if (crtc)
> + for_each_if ((__state)->crtcs[__i].ptr && \
> + ((crtc) = (__state)->crtcs[__i].ptr, \
> + (new_crtc_state) = (__state)->crtcs[__i].new_state, 1))
>
> /**
> * for_each_oldnew_plane_in_state - iterate over all planes in an atomic update
> @@ -705,12 +705,12 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_oldnew_plane_in_state(__state, plane, old_plane_state, new_plane_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_total_plane && \
> - ((plane) = (__state)->planes[__i].ptr, \
> - (old_plane_state) = (__state)->planes[__i].old_state, \
> - (new_plane_state) = (__state)->planes[__i].new_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_total_plane; \
> (__i)++) \
> - for_each_if (plane)
> + for_each_if ((__state)->planes[__i].ptr && \
> + ((plane) = (__state)->planes[__i].ptr, \
> + (old_plane_state) = (__state)->planes[__i].old_state,\
> + (new_plane_state) = (__state)->planes[__i].new_state, 1))
>
> /**
> * for_each_old_plane_in_state - iterate over all planes in an atomic update
> @@ -725,12 +725,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_old_plane_in_state(__state, plane, old_plane_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_total_plane && \
> - ((plane) = (__state)->planes[__i].ptr, \
> - (old_plane_state) = (__state)->planes[__i].old_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_total_plane; \
> (__i)++) \
> - for_each_if (plane)
> -
> + for_each_if ((__state)->planes[__i].ptr && \
> + ((plane) = (__state)->planes[__i].ptr, \
> + (old_plane_state) = (__state)->planes[__i].old_state, 1))
> /**
> * for_each_new_plane_in_state - iterate over all planes in an atomic update
> * @__state: &struct drm_atomic_state pointer
> @@ -744,11 +743,11 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> */
> #define for_each_new_plane_in_state(__state, plane, new_plane_state, __i) \
> for ((__i) = 0; \
> - (__i) < (__state)->dev->mode_config.num_total_plane && \
> - ((plane) = (__state)->planes[__i].ptr, \
> - (new_plane_state) = (__state)->planes[__i].new_state, 1); \
> + (__i) < (__state)->dev->mode_config.num_total_plane; \
> (__i)++) \
> - for_each_if (plane)
> + for_each_if ((__state)->planes[__i].ptr && \
> + ((plane) = (__state)->planes[__i].ptr, \
> + (new_plane_state) = (__state)->planes[__i].new_state, 1))
>
> /**
> * for_each_oldnew_private_obj_in_state - iterate over all private objects in an atomic update
> --
> 2.14.1
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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