gallium: Unify reference counting.

The core reference counting code is centralized in p_refcnt.h.

This has some consequences related to struct pipe_buffer:

* The screen member of struct pipe_buffer must be initialized, or
  pipe_buffer_reference() will crash trying to destroy a buffer with reference
  count 0. u_simple_screen takes care of this, but I may have missed some of
  the drivers not using it.
* Except for rare exceptions deep in winsys code, buffers must always be
  allocated via pipe_buffer_create() or via screen->*buffer_create() rather
  than via winsys->*buffer_create().

1 files changed, 3 insertions, 5 deletions

diff --git a/src/gallium/drivers/trace/tr_winsys.c b/src/gallium/drivers/trace/tr_winsys.c
index c4148fe8104..86420bbf22a 100644
--- a/src/gallium/drivers/trace/tr_winsys.c
+++ b/src/gallium/drivers/trace/tr_winsys.c
@@ -295,18 +295,16 @@ trace_winsys_buffer_unmap(struct pipe_winsys *_winsys,
 
 
 static void
-trace_winsys_buffer_destroy(struct pipe_winsys *_winsys,
-                            struct pipe_buffer *buffer)
+trace_winsys_buffer_destroy(struct pipe_buffer *buffer)
 {
-   struct trace_winsys *tr_ws = trace_winsys(_winsys);
-   struct pipe_winsys *winsys = tr_ws->winsys;
+   struct pipe_winsys *winsys = buffer->screen->winsys;
    
    trace_dump_call_begin("pipe_winsys", "buffer_destroy");
    
    trace_dump_arg(ptr, winsys);
    trace_dump_arg(ptr, buffer);
 
-   winsys->buffer_destroy(winsys, buffer);
+   winsys->buffer_destroy(buffer);
    
    trace_dump_call_end();
 }