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/winsys/xlib/xlib_cell.c b/src/gallium/winsys/xlib/xlib_cell.c
index 40bcdfe42a..a5dbdf30f6 100644
--- a/src/gallium/winsys/xlib/xlib_cell.c
+++ b/src/gallium/winsys/xlib/xlib_cell.c
@@ -243,7 +243,7 @@ xm_buffer_create(struct pipe_winsys *pws,
 {
    struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);
 
-   buffer->base.refcount = 1;
+   pipe_reference_init(&buffer->base.reference, 1);
    buffer->base.alignment = alignment;
    buffer->base.usage = usage;
    buffer->base.size = size;
@@ -267,7 +267,7 @@ static struct pipe_buffer *
 xm_user_buffer_create(struct pipe_winsys *pws, void *ptr, unsigned bytes)
 {
    struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);
-   buffer->base.refcount = 1;
+   pipe_reference_init(&buffer->base.reference, 1);
    buffer->base.size = bytes;
    buffer->userBuffer = TRUE;
    buffer->data = ptr;