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, 4 deletions

diff --git a/src/gallium/winsys/xlib/xlib_softpipe.c b/src/gallium/winsys/xlib/xlib_softpipe.c
index 71f12b2b47..762ebd9847 100644
--- a/src/gallium/winsys/xlib/xlib_softpipe.c
+++ b/src/gallium/winsys/xlib/xlib_softpipe.c
@@ -207,8 +207,7 @@ xm_buffer_unmap(struct pipe_winsys *pws, struct pipe_buffer *buf)
 }
 
 static void
-xm_buffer_destroy(struct pipe_winsys *pws,
-                  struct pipe_buffer *buf)
+xm_buffer_destroy(struct pipe_buffer *buf)
 {
    struct xm_buffer *oldBuf = xm_buffer(buf);
 
@@ -338,7 +337,7 @@ xm_buffer_create(struct pipe_winsys *pws,
    }
 #endif
 
-   buffer->base.refcount = 1;
+   pipe_reference_init(&buffer->base.reference, 1);
    buffer->base.alignment = alignment;
    buffer->base.usage = usage;
    buffer->base.size = size;
@@ -359,7 +358,7 @@ 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;