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, 3 deletions

diff --git a/src/gallium/drivers/nv50/nv50_query.c b/src/gallium/drivers/nv50/nv50_query.c
index 7c8831a46de..a2c56f99a89 100644
--- a/src/gallium/drivers/nv50/nv50_query.c
+++ b/src/gallium/drivers/nv50/nv50_query.c
@@ -41,13 +41,13 @@ nv50_query(struct pipe_query *pipe)
 static struct pipe_query *
 nv50_query_create(struct pipe_context *pipe, unsigned type)
 {
-	struct pipe_winsys *ws = pipe->winsys;
+	struct pipe_screen *screen = pipe->winsys;
 	struct nv50_query *q = CALLOC_STRUCT(nv50_query);
 
 	assert (q->type == PIPE_QUERY_OCCLUSION_COUNTER);
 	q->type = type;
 
-	q->buffer = ws->buffer_create(ws, 256, 0, 16);
+	q->buffer = screen->buffer_create(screen, 256, 0, 16);
 	if (!q->buffer) {
 		FREE(q);
 		return NULL;
@@ -62,7 +62,7 @@ nv50_query_destroy(struct pipe_context *pipe, struct pipe_query *pq)
 	struct nv50_query *q = nv50_query(pq);
 
 	if (q) {
-		pipe_buffer_reference(pipe->screen, &q->buffer, NULL);
+		pipe_buffer_reference(&q->buffer, NULL);
 		FREE(q);
 	}
 }