drm: atmel-hlcdc: add a ->cleanup_fb() operation

Add a ->cleanup_fb() operation to avoid memory leaks when the atomic
operation is interrupted after the ->prepare_fb() call.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes 2389fc1 ("drm: atmel-hlcdc: Atomic mode-setting conversion")
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Nicolas Ferre <nicolas.ferre@atmel.com>

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index d65dcae..2158d7a 100644 (file)
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -37,6 +37,7 @@
  * @xstride: value to add to the pixel pointer between each line
  * @pstride: value to add to the pixel pointer between each pixel
  * @nplanes: number of planes (deduced from pixel_format)
+ * @prepared: plane update has been prepared
  */
 struct atmel_hlcdc_plane_state {
        struct drm_plane_state base;
@@ -64,6 +65,7 @@ struct atmel_hlcdc_plane_state {
        int xstride[ATMEL_HLCDC_MAX_PLANES];
        int pstride[ATMEL_HLCDC_MAX_PLANES];
        int nplanes;
+       bool prepared;
 };
 
 static inline struct atmel_hlcdc_plane_state *
@@ -714,12 +716,54 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 static int atmel_hlcdc_plane_prepare_fb(struct drm_plane *p,
                                        const struct drm_plane_state *new_state)
 {
+       /*
+        * FIXME: we should avoid this const -> non-const cast but it's
+        * currently the only solution we have to modify the ->prepared
+        * state and rollback the update request.
+        * Ideally, we should rework the code to attach all the resources
+        * to atmel_hlcdc_plane_state (including the DMA desc allocation),
+        * but this require a complete rework of the atmel_hlcdc_layer
+        * code.
+        */
+       struct drm_plane_state *s = (struct drm_plane_state *)new_state;
        struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
+       struct atmel_hlcdc_plane_state *state =
+                       drm_plane_state_to_atmel_hlcdc_plane_state(s);
+       int ret;
 
-       if (!new_state->fb)
-               return 0;
+       ret = atmel_hlcdc_layer_update_start(&plane->layer);
+       if (!ret)
+               state->prepared = true;
+
+       return ret;
+}
+
+static void atmel_hlcdc_plane_cleanup_fb(struct drm_plane *p,
+                               const struct drm_plane_state *old_state)
+{
+       /*
+        * FIXME: we should avoid this const -> non-const cast but it's
+        * currently the only solution we have to modify the ->prepared
+        * state and rollback the update request.
+        * Ideally, we should rework the code to attach all the resources
+        * to atmel_hlcdc_plane_state (including the DMA desc allocation),
+        * but this require a complete rework of the atmel_hlcdc_layer
+        * code.
+        */
+       struct drm_plane_state *s = (struct drm_plane_state *)old_state;
+       struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
+       struct atmel_hlcdc_plane_state *state =
+                       drm_plane_state_to_atmel_hlcdc_plane_state(s);
+
+       /*
+        * The Request has already been applied or cancelled, nothing to do
+        * here.
+        */
+       if (!state->prepared)
+               return;
 
-       return atmel_hlcdc_layer_update_start(&plane->layer);
+       atmel_hlcdc_layer_update_rollback(&plane->layer);
+       state->prepared = false;
 }
 
 static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
@@ -844,6 +888,7 @@ static void atmel_hlcdc_plane_init_properties(struct atmel_hlcdc_plane *plane,
 
 static struct drm_plane_helper_funcs atmel_hlcdc_layer_plane_helper_funcs = {
        .prepare_fb = atmel_hlcdc_plane_prepare_fb,
+       .cleanup_fb = atmel_hlcdc_plane_cleanup_fb,
        .atomic_check = atmel_hlcdc_plane_atomic_check,
        .atomic_update = atmel_hlcdc_plane_atomic_update,
        .atomic_disable = atmel_hlcdc_plane_atomic_disable,
@@ -883,6 +928,7 @@ atmel_hlcdc_plane_atomic_duplicate_state(struct drm_plane *p)
                return NULL;
 
        copy->disc_updated = false;
+       copy->prepared = false;
 
        if (copy->base.fb)
                drm_framebuffer_reference(copy->base.fb);