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/drm/nouveau/common/nouveau_context.c b/src/gallium/winsys/drm/nouveau/common/nouveau_context.c
index d6ae0827cd..25c98456ac 100644
--- a/src/gallium/winsys/drm/nouveau/common/nouveau_context.c
+++ b/src/gallium/winsys/drm/nouveau/common/nouveau_context.c
@@ -109,8 +109,7 @@ nouveau_context_init(struct nouveau_screen *nv_screen,
 		nv_screen->nvc = nvc;
 	}
 
-	nvc->refcount++;
-	nv->nvc = nvc;
+	pipe_reference((struct pipe_reference**)&nv->nvc, &nvc->reference);
 
 	/* Find a free slot for a pipe context, allocate a new one if needed */
 	nv->pctx_id = -1;
@@ -159,7 +158,7 @@ nouveau_context_init(struct nouveau_screen *nv_screen,
 		enum pipe_format format;
 
 		fb_buf = calloc(1, sizeof(struct nouveau_pipe_buffer));
-		fb_buf->base.refcount = 1;
+		pipe_reference_init(&fb_buf->base.reference, 1);
 		fb_buf->base.usage = PIPE_BUFFER_USAGE_PIXEL;
 
 		nouveau_bo_fake(dev, nv_screen->front_offset, NOUVEAU_BO_VRAM,
@@ -195,7 +194,7 @@ nouveau_context_cleanup(struct nouveau_context *nv)
 
 	if (nv->pctx_id >= 0) {
 		nvc->pctx[nv->pctx_id] = NULL;
-		if (--nvc->refcount <= 0) {
+		if (pipe_reference((struct pipe_reference**)&nv->nvc, NULL)) {
 			nouveau_channel_context_destroy(nvc);
 			nv->nv_screen->nvc = NULL;
 		}