[Mesa-dev] [PATCH] intel: Fix size of temporary etc1 buffer

[Chad Versace]

Fixes valgrind errors in piglit test
oes_compressed_etc1_rgb8_texture-miptree: an invalid write in
_mesa_store_compressed_store_texsubimage() at line 4406 and invalid reads
in texcompress_etc_tmp.h:etc1_parse_block().

The calculation of the size of the temporary etc1 buffer allocated by
intel_miptree_map_etc1() was incorrect. Sometimes the allocated buffer was
too small, sometimes too large.  This patch corrects the size to that
expected by _mesa_store_compressed_store_texsubimage().

Note: This is candidate for the 9.0 branch.
CC: Oliver McFadden <oliver.mcfadden at linux.intel.com>
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/drivers/dri/intel/intel_mipmap_tree.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
index 556a82f..c2266a4 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
@@ -1273,6 +1273,14 @@ intel_miptree_map_etc1(struct intel_context *intel,
                        unsigned int level,
                        unsigned int slice)
 {
+   const int block_width = 4; /*in pixels*/
+   const int block_height = 4; /*in pixels*/
+   const int block_size = 8; /*in bytes*/
+
+   /* Size of a row of blocks, in bytes. */
+   const int row_size = block_size * ALIGN(map->w, block_width) / block_width;
+   const int num_rows = ALIGN(map->h, block_height) / block_height;
+
    /* For justification of these invariants,
     * see intel_mipmap_tree:wraps_etc1.
     */
@@ -1292,9 +1300,8 @@ intel_miptree_map_etc1(struct intel_context *intel,
    assert(map->x == 0);
    assert(map->y == 0);
 
-   /* Each ETC1 block contains 4x4 pixels in 8 bytes. */
-   map->stride = 2 * map->w;
-   map->buffer = map->ptr = malloc(map->stride * map->h);
+   map->stride = row_size;
+   map->buffer = map->ptr = malloc(row_size * num_rows);
 }
 
 static void
-- 
1.7.12