[PATCH 2/2] drm/atomic: Make atomic iterators less surprising

[Maarten Lankhorst]

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.

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