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, 4 insertions, 12 deletions

diff --git a/src/gallium/drivers/i915simple/i915_screen.c b/src/gallium/drivers/i915simple/i915_screen.c
index 4947128..f4aa8e6 100644
--- a/src/gallium/drivers/i915simple/i915_screen.c
+++ b/src/gallium/drivers/i915simple/i915_screen.c
@@ -230,7 +230,6 @@ i915_get_tex_transfer(struct pipe_screen *screen,
 
    trans = CALLOC_STRUCT(i915_transfer);
    if (trans) {
-      trans->base.refcount = 1;
       pipe_texture_reference(&trans->base.texture, texture);
       trans->base.format = trans->base.format;
       trans->base.width = w;
@@ -246,17 +245,10 @@ i915_get_tex_transfer(struct pipe_screen *screen,
 }
 
 static void
-i915_tex_transfer_release(struct pipe_screen *screen,
-                          struct pipe_transfer **transfer)
+i915_tex_transfer_destroy(struct pipe_transfer *trans)
 {
-   struct pipe_transfer *trans = *transfer;
-
-   if (--trans->refcount == 0) {
-      pipe_texture_reference(&trans->texture, NULL);
-      FREE(trans);
-   }
-
-   *transfer = NULL;
+   pipe_texture_reference(&trans->texture, NULL);
+   FREE(trans);
 }
 
 static void *
@@ -344,7 +336,7 @@ i915_create_screen(struct pipe_winsys *winsys, uint pci_id)
    i915screen->screen.get_paramf = i915_get_paramf;
    i915screen->screen.is_format_supported = i915_is_format_supported;
    i915screen->screen.get_tex_transfer = i915_get_tex_transfer;
-   i915screen->screen.tex_transfer_release = i915_tex_transfer_release;
+   i915screen->screen.tex_transfer_destroy = i915_tex_transfer_destroy;
    i915screen->screen.transfer_map = i915_transfer_map;
    i915screen->screen.transfer_unmap = i915_transfer_unmap;