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, 1 insertions, 1 deletions

diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index 78a7956c90d..f31be690237 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -209,7 +209,7 @@ static void st_destroy_context_priv( struct st_context *st )
 
    for (i = 0; i < Elements(st->state.constants); i++) {
       if (st->state.constants[i].buffer) {
-         pipe_buffer_reference(st->pipe->screen, &st->state.constants[i].buffer, NULL);
+         pipe_buffer_reference(&st->state.constants[i].buffer, NULL);
       }
    }