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, 2 insertions, 2 deletions

diff --git a/src/gallium/drivers/trace/tr_texture.c b/src/gallium/drivers/trace/tr_texture.c
index 120ba0dd31..dc45d3dcc1 100644
--- a/src/gallium/drivers/trace/tr_texture.c
+++ b/src/gallium/drivers/trace/tr_texture.c
@@ -134,7 +134,7 @@ trace_transfer_create(struct trace_texture *tr_tex,
    return &tr_trans->base;
    
 error:
-   pipe_transfer_reference(&transfer, NULL);
+   transfer->texture->screen->tex_transfer_destroy(transfer);
    return NULL;
 }
 
@@ -145,7 +145,7 @@ trace_transfer_destroy(struct trace_texture *tr_tex,
 {
    struct trace_transfer *tr_trans = trace_transfer(tr_tex, transfer);
    pipe_texture_reference(&tr_trans->base.texture, NULL);
-   pipe_transfer_reference(&tr_trans->transfer, NULL);
+   transfer->texture->screen->tex_transfer_destroy(tr_trans->transfer);
    FREE(tr_trans);
 }