mesa: allow buffers to be mapped multiple times

OpenGL allows a buffer to be mapped only once, but we also map buffers
internally, e.g. in the software primitive restart fallback, for PBOs,
vbo_get_minmax_index, etc. This has always been a problem, but it will
be a bigger problem with persistent buffer mappings, which will prevent
all Mesa functions from mapping buffers for internal purposes.

This adds a driver interface to core Mesa which supports multiple buffer
mappings and allows 2 mappings: one for the GL user and one for Mesa.

Note that Gallium supports an unlimited number of buffer and texture
mappings, so it's not really an issue for Gallium.

v2: fix unmapping in xm_dd.c, remove the GL errors there
v3: fix the intel driver (by Fredrik)

Reviewed-by: Fredrik Höglund <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/mesa/state_tracker/st_cb_bufferobjects.h b/src/mesa/state_tracker/st_cb_bufferobjects.h
index a039c0a5059..a5ab122190a 100644
--- a/src/mesa/state_tracker/st_cb_bufferobjects.h
+++ b/src/mesa/state_tracker/st_cb_bufferobjects.h
@@ -43,7 +43,7 @@ struct st_buffer_object
 {
    struct gl_buffer_object Base;
    struct pipe_resource *buffer;     /* GPU storage */
-   struct pipe_transfer *transfer; /* In-progress map information */
+   struct pipe_transfer *transfer[MAP_COUNT];
 };