On 22.01.2016 02:53, Jordan Justen wrote:
Juha-Pekka found this back in May 2015:
<1430915727-28677-1-git-send-email-juhapekka.heikk...@gmail.com>
From the discussion, obviously it would be preferable to make
ralloc_size no longer return zeroed memory, but Juha-Pekka found that
it would break Mesa.
For now, let's point out the flaw, and stop doing the double zeroing
of rzalloc buffers.
Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Juha-Pekka Heikkila <juhapekka.heikk...@gmail.com>
Cc: Kenneth Graunke <kenn...@whitecape.org>
---
For a release build, I saw the code size shrink by 64 bytes.
src/util/ralloc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/src/util/ralloc.c b/src/util/ralloc.c
index 6d4032b..24c1eee 100644
--- a/src/util/ralloc.c
+++ b/src/util/ralloc.c
@@ -49,6 +49,14 @@ _CRTIMP int _vscprintf(const char *format, va_list argptr);
#endif
#endif
+/* ralloc_size has always used calloc to allocate memory. This has allowed
+ * code using ralloc_size to depend on always receiving a cleared buffer.
+ *
+ * FIXME: Clean up the code base to allow this to be set to false, and then
+ * remove it altogether.
+ */
+static const bool always_allocate_zeroed_memory = true;
+
#define CANARY 0x5A1106
struct ralloc_header
@@ -110,7 +118,10 @@ ralloc_context(const void *ctx)
void *
ralloc_size(const void *ctx, size_t size)
{
- void *block = calloc(1, size + sizeof(ralloc_header));
+ void *block =
+ always_allocate_zeroed_memory ?
+ calloc(1, size + sizeof(ralloc_header)) :
+ malloc(size + sizeof(ralloc_header));
There's an integer overflow here which would be good to fix. Since it
was there already in the older version, the patch is
Reviewed-by: Nicolai Hähnle <nicolai.haeh...@amd.com>
as is.
ralloc_header *info;
ralloc_header *parent;
@@ -132,7 +143,7 @@ void *
rzalloc_size(const void *ctx, size_t size)
{
void *ptr = ralloc_size(ctx, size);
- if (likely(ptr != NULL))
+ if (!always_allocate_zeroed_memory && likely(ptr != NULL))
memset(ptr, 0, size);
return ptr;
}
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