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().

15 files changed, 58 insertions, 62 deletions

diff --git a/src/mesa/state_tracker/st_atom_constbuf.c b/src/mesa/state_tracker/st_atom_constbuf.c
index 2df6fef210e..fd81ac36d2c 100644
--- a/src/mesa/state_tracker/st_atom_constbuf.c
+++ b/src/mesa/state_tracker/st_atom_constbuf.c
@@ -73,7 +73,7 @@ void st_upload_constants( struct st_context *st,
       /* We always need to get a new buffer, to keep the drivers simple and
        * avoid gratuitous rendering synchronization.
        */
-      pipe_buffer_reference(pipe->screen, &cbuf->buffer, NULL );
+      pipe_buffer_reference(&cbuf->buffer, NULL );
       cbuf->buffer = pipe_buffer_create(pipe->screen, 16, PIPE_BUFFER_USAGE_CONSTANT,
 					paramBytes );
 
diff --git a/src/mesa/state_tracker/st_atom_pixeltransfer.c b/src/mesa/state_tracker/st_atom_pixeltransfer.c
index 05b69c9d00a..347f2b60c38 100644
--- a/src/mesa/state_tracker/st_atom_pixeltransfer.c
+++ b/src/mesa/state_tracker/st_atom_pixeltransfer.c
@@ -171,7 +171,7 @@ load_color_map_texture(GLcontext *ctx, struct pipe_texture *pt)
    }
 
    screen->transfer_unmap(screen, transfer);
-   screen->tex_transfer_release(screen, &transfer);
+   screen->tex_transfer_destroy(transfer);
 }
 
 
diff --git a/src/mesa/state_tracker/st_cb_accum.c b/src/mesa/state_tracker/st_cb_accum.c
index 15cc4cd95dc..3f9a825a153 100644
--- a/src/mesa/state_tracker/st_cb_accum.c
+++ b/src/mesa/state_tracker/st_cb_accum.c
@@ -149,7 +149,7 @@ st_clear_accum_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
    }
 
    screen->transfer_unmap(screen, acc_pt);
-   screen->tex_transfer_release(screen, &acc_pt);
+   screen->tex_transfer_destroy(acc_pt);
 }
 
 
@@ -187,7 +187,7 @@ accum_mad(GLcontext *ctx, GLfloat scale, GLfloat bias,
    }
 
    screen->transfer_unmap(screen, acc_pt);
-   screen->tex_transfer_release(screen, &acc_pt);
+   screen->tex_transfer_destroy(acc_pt);
 }
 
 
@@ -220,7 +220,7 @@ accum_accum(struct pipe_context *pipe, GLfloat value,
       accBuf[i] = accBuf[i] + colorBuf[i] * value;
    }
 
-   screen->tex_transfer_release(screen, &acc_trans);
+   screen->tex_transfer_destroy(acc_trans);
    acc_trans = screen->get_tex_transfer(screen, acc_strb->texture, 0, 0, 0,
                                         PIPE_TRANSFER_WRITE, xpos, ypos,
                                         width, height);
@@ -229,8 +229,8 @@ accum_accum(struct pipe_context *pipe, GLfloat value,
 
    _mesa_free(colorBuf);
    _mesa_free(accBuf);
-   screen->tex_transfer_release(screen, &acc_trans);
-   screen->tex_transfer_release(screen, &color_trans);
+   screen->tex_transfer_destroy(acc_trans);
+   screen->tex_transfer_destroy(color_trans);
 }
 
 
@@ -264,8 +264,8 @@ accum_load(struct pipe_context *pipe, GLfloat value,
    acc_put_tile_rgba(pipe, acc_trans, 0, 0, width, height, buf);
 
    _mesa_free(buf);
-   screen->tex_transfer_release(screen, &acc_trans);
-   screen->tex_transfer_release(screen, &color_trans);
+   screen->tex_transfer_destroy(acc_trans);
+   screen->tex_transfer_destroy(color_trans);
 }
 
 
@@ -316,8 +316,8 @@ accum_return(GLcontext *ctx, GLfloat value,
    _mesa_free(abuf);
    if (cbuf)
       _mesa_free(cbuf);
-   screen->tex_transfer_release(screen, &acc_trans);
-   screen->tex_transfer_release(screen, &color_trans);
+   screen->tex_transfer_destroy(acc_trans);
+   screen->tex_transfer_destroy(color_trans);
 }
 
 
diff --git a/src/mesa/state_tracker/st_cb_bitmap.c b/src/mesa/state_tracker/st_cb_bitmap.c
index f55a5e713ff..f77ac14762f 100644
--- a/src/mesa/state_tracker/st_cb_bitmap.c
+++ b/src/mesa/state_tracker/st_cb_bitmap.c
@@ -351,7 +351,7 @@ make_bitmap_texture(GLcontext *ctx, GLsizei width, GLsizei height,
 
    /* Release transfer */
    screen->transfer_unmap(screen, transfer);
-   screen->tex_transfer_release(screen, &transfer);
+   screen->tex_transfer_destroy(transfer);
 
    return pt;
 }
@@ -379,7 +379,7 @@ setup_bitmap_vertex_data(struct st_context *st,
    GLuint i;
 
    if (st->bitmap.vbuf_slot >= max_slots) {
-      pipe_buffer_reference(pipe->screen, &st->bitmap.vbuf, NULL);
+      pipe_buffer_reference(&st->bitmap.vbuf, NULL);
       st->bitmap.vbuf_slot = 0;
    }
 
@@ -571,7 +571,7 @@ reset_cache(struct st_context *st)
    cache->ymax = -1000000;
 
    if (cache->trans)
-      screen->tex_transfer_release(screen, &cache->trans);
+      screen->tex_transfer_destroy(cache->trans);
 
    assert(!cache->texture);
 
@@ -623,7 +623,7 @@ st_flush_bitmap_cache(struct st_context *st)
          screen->transfer_unmap(screen, cache->trans);
          cache->buffer = NULL;
 
-         screen->tex_transfer_release(screen, &cache->trans);
+         screen->tex_transfer_destroy(cache->trans);
 
          draw_bitmap_quad(st->ctx,
                           cache->xpos,
@@ -651,7 +651,7 @@ st_flush_bitmap( struct st_context *st )
    /* Release vertex buffer to avoid synchronous rendering if we were
     * to map it in the next frame.
     */
-   pipe_buffer_reference(st->pipe->screen, &st->bitmap.vbuf, NULL);
+   pipe_buffer_reference(&st->bitmap.vbuf, NULL);
    st->bitmap.vbuf_slot = 0;
 }
 
@@ -819,7 +819,7 @@ st_destroy_bitmap(struct st_context *st)
    struct bitmap_cache *cache = st->bitmap.cache;
 
    screen->transfer_unmap(screen, cache->trans);
-   screen->tex_transfer_release(screen, &cache->trans);
+   screen->tex_transfer_destroy(cache->trans);
 
    if (st->bitmap.vs) {
       cso_delete_vertex_shader(st->cso_context, st->bitmap.vs);
@@ -828,12 +828,12 @@ st_destroy_bitmap(struct st_context *st)
    util_free_shader(&st->bitmap.vert_shader);
 
    if (st->bitmap.vbuf) {
-      pipe_buffer_reference(pipe->screen, &st->bitmap.vbuf, NULL);
+      pipe_buffer_reference(&st->bitmap.vbuf, NULL);
       st->bitmap.vbuf = NULL;
    }
 
    if (st->bitmap.cache) {
-      pipe_texture_release(&st->bitmap.cache->texture);
+      pipe_texture_reference(&st->bitmap.cache->texture, NULL);
       _mesa_free(st->bitmap.cache);
       st->bitmap.cache = NULL;
    }
diff --git a/src/mesa/state_tracker/st_cb_bufferobjects.c b/src/mesa/state_tracker/st_cb_bufferobjects.c
index 28e387c399d..52099232ade 100644
--- a/src/mesa/state_tracker/st_cb_bufferobjects.c
+++ b/src/mesa/state_tracker/st_cb_bufferobjects.c
@@ -74,11 +74,10 @@ st_bufferobj_alloc(GLcontext *ctx, GLuint name, GLenum target)
 static void
 st_bufferobj_free(GLcontext *ctx, struct gl_buffer_object *obj)
 {
-   struct pipe_context *pipe = st_context(ctx)->pipe;
    struct st_buffer_object *st_obj = st_buffer_object(obj);
 
    if (st_obj->buffer) 
-      pipe_buffer_reference(pipe->screen, &st_obj->buffer, NULL);
+      pipe_buffer_reference(&st_obj->buffer, NULL);
 
    _mesa_free(st_obj);
 }
@@ -165,7 +164,7 @@ st_bufferobj_data(GLcontext *ctx,
       buffer_usage = 0;
    }
 
-   pipe_buffer_reference( pipe->screen, &st_obj->buffer, NULL );
+   pipe_buffer_reference( &st_obj->buffer, NULL );
 
    st_obj->buffer = pipe_buffer_create( pipe->screen, 32, buffer_usage, size );
 
diff --git a/src/mesa/state_tracker/st_cb_clear.c b/src/mesa/state_tracker/st_cb_clear.c
index c6fc7cec27c..7d4948a64ea 100644
--- a/src/mesa/state_tracker/st_cb_clear.c
+++ b/src/mesa/state_tracker/st_cb_clear.c
@@ -95,8 +95,6 @@ st_init_clear(struct st_context *st)
 void
 st_destroy_clear(struct st_context *st)
 {
-   struct pipe_context *pipe = st->pipe;
-
    if (st->clear.vert_shader.tokens) {
       util_free_shader(&st->clear.vert_shader);
       st->clear.vert_shader.tokens = NULL;
@@ -116,7 +114,7 @@ st_destroy_clear(struct st_context *st)
       st->clear.vs = NULL;
    }
    if (st->clear.vbuf) {
-      pipe_buffer_reference(pipe->screen, &st->clear.vbuf, NULL);
+      pipe_buffer_reference(&st->clear.vbuf, NULL);
       st->clear.vbuf = NULL;
    }
 }
@@ -152,7 +150,7 @@ draw_quad(GLcontext *ctx,
    GLuint i;
 
    if (st->clear.vbuf_slot >= max_slots) {
-      pipe_buffer_reference(pipe->screen, &st->clear.vbuf, NULL);
+      pipe_buffer_reference(&st->clear.vbuf, NULL);
       st->clear.vbuf_slot = 0;
    }
 
@@ -524,7 +522,7 @@ void st_flush_clear( struct st_context *st )
    /* Release vertex buffer to avoid synchronous rendering if we were
     * to map it in the next frame.
     */
-   pipe_buffer_reference(st->pipe->screen, &st->clear.vbuf, NULL);
+   pipe_buffer_reference(&st->clear.vbuf, NULL);
    st->clear.vbuf_slot = 0;
 }
  
diff --git a/src/mesa/state_tracker/st_cb_drawpixels.c b/src/mesa/state_tracker/st_cb_drawpixels.c
index cc7a9e78907..0a09e7e6f19 100644
--- a/src/mesa/state_tracker/st_cb_drawpixels.c
+++ b/src/mesa/state_tracker/st_cb_drawpixels.c
@@ -392,7 +392,7 @@ make_texture(struct st_context *st,
 
       /* unmap */
       screen->transfer_unmap(screen, transfer);
-      screen->tex_transfer_release(screen, &transfer);
+      screen->tex_transfer_destroy(transfer);
 
       assert(success);
 
@@ -495,7 +495,7 @@ draw_quad(GLcontext *ctx, GLfloat x0, GLfloat y0, GLfloat z,
                               PIPE_PRIM_QUADS,
                               4,  /* verts */
                               3); /* attribs/vert */
-      pipe_buffer_reference(pipe->screen, &buf, NULL);
+      pipe_buffer_reference(&buf, NULL);
    }
 }
 
@@ -808,7 +808,7 @@ draw_stencil_pixels(GLcontext *ctx, GLint x, GLint y,
 
    /* unmap the stencil buffer */
    screen->transfer_unmap(screen, pt);
-   screen->tex_transfer_release(screen, &pt);
+   screen->tex_transfer_destroy(pt);
 }
 
 
@@ -951,7 +951,7 @@ copy_stencil_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 
    /* unmap the stencil buffer */
    screen->transfer_unmap(screen, ptDraw);
-   screen->tex_transfer_release(screen, &ptDraw);
+   screen->tex_transfer_destroy(ptDraw);
 }
 
 
@@ -1070,8 +1070,8 @@ st_CopyPixels(GLcontext *ctx, GLint srcx, GLint srcy,
          _mesa_free(buf);
       }
 
-      screen->tex_transfer_release(screen, &ptRead);
-      screen->tex_transfer_release(screen, &ptTex);
+      screen->tex_transfer_destroy(ptRead);
+      screen->tex_transfer_destroy(ptTex);
    }
 
    /* draw textured quad */
diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
index 4e669f113bf..121ca8c29a7 100644
--- a/src/mesa/state_tracker/st_cb_fbo.c
+++ b/src/mesa/state_tracker/st_cb_fbo.c
@@ -413,7 +413,6 @@ static void
 st_finish_render_texture(GLcontext *ctx,
                          struct gl_renderbuffer_attachment *att)
 {
-   struct pipe_screen *screen = ctx->st->pipe->screen;
    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 
    if (!strb)
@@ -422,7 +421,7 @@ st_finish_render_texture(GLcontext *ctx,
    st_flush( ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL );
 
    if (strb->surface)
-      screen->tex_surface_release( screen, &strb->surface );
+      pipe_surface_reference( &strb->surface, NULL );
 
    strb->rtt = NULL;
 
diff --git a/src/mesa/state_tracker/st_cb_readpixels.c b/src/mesa/state_tracker/st_cb_readpixels.c
index 5a4a7f0a616..2a4beccd90e 100644
--- a/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/src/mesa/state_tracker/st_cb_readpixels.c
@@ -134,7 +134,7 @@ st_read_stencil_pixels(GLcontext *ctx, GLint x, GLint y,
 
    /* unmap the stencil buffer */
    screen->transfer_unmap(screen, pt);
-   screen->tex_transfer_release(screen, &pt);
+   screen->tex_transfer_destroy(pt);
 }
 
 
@@ -224,7 +224,7 @@ st_fast_readpixels(GLcontext *ctx, struct st_renderbuffer *strb,
 
       map = screen->transfer_map(screen, trans);
       if (!map) {
-         screen->tex_transfer_release(screen, &trans);
+         screen->tex_transfer_destroy(trans);
          return GL_FALSE;
       }
 
@@ -282,7 +282,7 @@ st_fast_readpixels(GLcontext *ctx, struct st_renderbuffer *strb,
       }
 
       screen->transfer_unmap(screen, trans);
-      screen->tex_transfer_release(screen, &trans);
+      screen->tex_transfer_destroy(trans);
    }
 
    return GL_TRUE;
@@ -466,7 +466,7 @@ st_readpixels(GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
       }
    }
 
-   screen->tex_transfer_release(screen, &trans);
+   screen->tex_transfer_destroy(trans);
 
    _mesa_unmap_readpix_pbo(ctx, &clippedPacking);
 }
diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index 3039eb2a877..a5044541459 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -938,12 +938,12 @@ fallback_copy_texsubimage(GLcontext *ctx,
       srcY = strb->Base.Height - srcY - height;
    }
 
-   src_trans = pipe->screen->get_tex_transfer( pipe->screen,
-                                               strb->texture,
-                                               0, 0, 0,
-                                               PIPE_TRANSFER_READ,
-                                               srcX, srcY,
-                                               width, height);
+   src_trans = screen->get_tex_transfer( screen,
+                                         strb->texture,
+                                         0, 0, 0,
+                                         PIPE_TRANSFER_READ,
+                                         srcX, srcY,
+                                         width, height);
 
    texDest = st_texture_image_map(ctx->st, stImage, 0, PIPE_TRANSFER_WRITE,
                                   destX, destY, width, height);
@@ -1020,7 +1020,7 @@ fallback_copy_texsubimage(GLcontext *ctx,
    }
 
    st_texture_image_unmap(ctx->st, stImage);
-   screen->tex_transfer_release(screen, &src_trans);
+   screen->tex_transfer_destroy(src_trans);
 }
 
 
@@ -1413,7 +1413,7 @@ st_finalize_texture(GLcontext *ctx,
           stObj->pt->depth[0] != firstImage->base.Depth2 ||
           stObj->pt->block.size/stObj->pt->block.width != cpp || /* Nominal bytes per pixel */
           stObj->pt->compressed != firstImage->base.IsCompressed) {
-         pipe_texture_release(&stObj->pt);
+         pipe_texture_reference(&stObj->pt, NULL);
          ctx->st->dirty.st |= ST_NEW_FRAMEBUFFER;
       }
    }
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);
       }
    }
 
diff --git a/src/mesa/state_tracker/st_draw.c b/src/mesa/state_tracker/st_draw.c
index b52e4886128..be1d9a86281 100644
--- a/src/mesa/state_tracker/st_draw.c
+++ b/src/mesa/state_tracker/st_draw.c
@@ -378,7 +378,7 @@ setup_interleaved_attribs(GLcontext *ctx,
          }
          else {
             vbuffer->buffer = NULL;
-            pipe_buffer_reference(pipe->screen, &vbuffer->buffer, stobj->buffer);
+            pipe_buffer_reference(&vbuffer->buffer, stobj->buffer);
             vbuffer->buffer_offset = (unsigned) low;
          }
          vbuffer->stride = stride; /* in bytes */
@@ -433,7 +433,7 @@ setup_non_interleaved_attribs(GLcontext *ctx,
          /*printf("stobj %u = %p\n", attr, (void*) stobj);*/
 
          vbuffer[attr].buffer = NULL;
-         pipe_buffer_reference(pipe->screen, &vbuffer[attr].buffer, stobj->buffer);
+         pipe_buffer_reference(&vbuffer[attr].buffer, stobj->buffer);
          vbuffer[attr].buffer_offset = (unsigned) arrays[mesaAttr]->Ptr;
          velements[attr].src_offset = 0;
       }
@@ -617,7 +617,7 @@ st_draw_vbo(GLcontext *ctx,
       if (bufobj && bufobj->Name) {
          /* elements/indexes are in a real VBO */
          struct st_buffer_object *stobj = st_buffer_object(bufobj);
-         pipe_buffer_reference(pipe->screen, &indexBuf, stobj->buffer);
+         pipe_buffer_reference(&indexBuf, stobj->buffer);
          indexOffset = (unsigned) ib->ptr / indexSize;
       }
       else {
@@ -657,7 +657,7 @@ st_draw_vbo(GLcontext *ctx,
          }
       }
 
-      pipe_buffer_reference(pipe->screen, &indexBuf, NULL);
+      pipe_buffer_reference(&indexBuf, NULL);
    }
    else {
       /* non-indexed */
@@ -673,7 +673,7 @@ st_draw_vbo(GLcontext *ctx,
 
    /* unreference buffers (frees wrapped user-space buffer objects) */
    for (attr = 0; attr < num_vbuffers; attr++) {
-      pipe_buffer_reference(pipe->screen, &vbuffer[attr].buffer, NULL);
+      pipe_buffer_reference(&vbuffer[attr].buffer, NULL);
       assert(!vbuffer[attr].buffer);
    }
 
diff --git a/src/mesa/state_tracker/st_draw_feedback.c b/src/mesa/state_tracker/st_draw_feedback.c
index 5c9c4506c22..d63d8cae28e 100644
--- a/src/mesa/state_tracker/st_draw_feedback.c
+++ b/src/mesa/state_tracker/st_draw_feedback.c
@@ -152,7 +152,7 @@ st_feedback_draw_vbo(GLcontext *ctx,
          assert(stobj->buffer);
 
          vbuffers[attr].buffer = NULL;
-         pipe_buffer_reference(pipe->screen, &vbuffers[attr].buffer, stobj->buffer);
+         pipe_buffer_reference(&vbuffers[attr].buffer, stobj->buffer);
          vbuffers[attr].buffer_offset = (unsigned) arrays[0]->Ptr;/* in bytes */
          velements[attr].src_offset = arrays[mesaAttr]->Ptr - arrays[0]->Ptr;
       }
@@ -248,7 +248,7 @@ st_feedback_draw_vbo(GLcontext *ctx,
    for (i = 0; i < PIPE_MAX_ATTRIBS; i++) {
       if (draw->pt.vertex_buffer[i].buffer) {
          pipe_buffer_unmap(pipe->screen, draw->pt.vertex_buffer[i].buffer);
-         pipe_buffer_reference(pipe->screen, &draw->pt.vertex_buffer[i].buffer, NULL);
+         pipe_buffer_reference(&draw->pt.vertex_buffer[i].buffer, NULL);
          draw_set_mapped_vertex_buffer(draw, i, NULL);
       }
    }
diff --git a/src/mesa/state_tracker/st_gen_mipmap.c b/src/mesa/state_tracker/st_gen_mipmap.c
index 08e48030681..9cc2176d5e4 100644
--- a/src/mesa/state_tracker/st_gen_mipmap.c
+++ b/src/mesa/state_tracker/st_gen_mipmap.c
@@ -147,8 +147,8 @@ fallback_generate_mipmap(GLcontext *ctx, GLenum target,
       screen->transfer_unmap(screen, srcTrans);
       screen->transfer_unmap(screen, dstTrans);
 
-      screen->tex_transfer_release(screen, &srcTrans);
-      screen->tex_transfer_release(screen, &dstTrans);
+      screen->tex_transfer_destroy(srcTrans);
+      screen->tex_transfer_destroy(dstTrans);
    }
 }
 
diff --git a/src/mesa/state_tracker/st_texture.c b/src/mesa/state_tracker/st_texture.c
index fcf76ef82e8..79a4bd84d01 100644
--- a/src/mesa/state_tracker/st_texture.c
+++ b/src/mesa/state_tracker/st_texture.c
@@ -108,7 +108,7 @@ st_texture_create(struct st_context *st,
 
    newtex = screen->texture_create(screen, &pt);
 
-   assert(!newtex || newtex->refcount == 1);
+   assert(!newtex || newtex->reference.count == 1);
 
    return newtex;
 }
@@ -219,7 +219,7 @@ st_texture_image_unmap(struct st_context *st,
 
    screen->transfer_unmap(screen, stImage->transfer);
 
-   screen->tex_transfer_release(screen, &stImage->transfer);
+   screen->tex_transfer_destroy(stImage->transfer);
 }
 
 
@@ -284,7 +284,7 @@ st_texture_image_data(struct pipe_context *pipe,
 		      0, 0,                             /* source x, y */
 		      dst->width[level], dst->height[level]);       /* width, height */
 
-      screen->tex_transfer_release(screen, &dst_transfer);
+      screen->tex_transfer_destroy(dst_transfer);
 
       srcUB += src_image_stride;
    }
@@ -350,8 +350,8 @@ st_texture_image_copy(struct pipe_context *pipe,
 			 0, 0, /* srcX, Y */
 			 width, height);
 
-      screen->tex_surface_release(screen, &src_surface);
-      screen->tex_surface_release(screen, &dst_surface);
+      pipe_surface_reference(&src_surface, NULL);
+      pipe_surface_reference(&dst_surface, NULL);
    }
 }