[mutter] renderer/native: assert dumb buffer size on CPU copy

[Jonas Ådahl <jadahl src gnome org>]

commit 72e236106f96ae9410e2a6dc6f2f2ac6fe26d224
Author: Pekka Paalanen <pekka paalanen collabora co uk>
Date:   Wed Sep 5 11:48:08 2018 +0300

    renderer/native: assert dumb buffer size on CPU copy
    
    Track the allocated dumb buffer size in MetaDumbBuffer. Assert that the
    size is as expected in copy_shared_framebuffer_cpu().
    
    This is just to ensure that Cogl and the real size match. The size from
    Cogl was used in the copy, so getting that wrong might have written
    beyond the allocation.
    
    This is a safety measure and has not been observed to happen yet.

 src/backends/native/meta-renderer-native.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
index 6eaa0b45f..eb7f087d0 100644
--- a/src/backends/native/meta-renderer-native.c
+++ b/src/backends/native/meta-renderer-native.c
@@ -124,6 +124,8 @@ typedef struct _MetaDumbBuffer
   uint32_t handle;
   void *map;
   uint64_t map_size;
+  int width;
+  int height;
 } MetaDumbBuffer;
 
 typedef struct _MetaOnscreenNativeSecondaryGpuState
@@ -1798,6 +1800,9 @@ copy_shared_framebuffer_cpu (CoglOnscreen                        *onscreen,
     next_dumb_fb = &secondary_gpu_state->cpu.dumb_fbs[0];
   secondary_gpu_state->cpu.dumb_fb = next_dumb_fb;
 
+  g_assert (width == secondary_gpu_state->cpu.dumb_fb->width);
+  g_assert (height == secondary_gpu_state->cpu.dumb_fb->height);
+
   target_data = secondary_gpu_state->cpu.dumb_fb->map;
   target_fb_id = secondary_gpu_state->cpu.dumb_fb->fb_id;
 
@@ -2299,6 +2304,8 @@ init_dumb_fb (MetaDumbBuffer  *dumb_fb,
   dumb_fb->handle = create_arg.handle;
   dumb_fb->map = map;
   dumb_fb->map_size = create_arg.size;
+  dumb_fb->width = width;
+  dumb_fb->height = height;
 
   return TRUE;