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, 3 insertions, 2 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index cbaf67b4367..d42c074cd31 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -861,12 +861,13 @@ static void brw_upload_indices(struct brw_context *brw)
                                                     offset,
                                                     ib_size,
                                                     GL_MAP_READ_BIT,
-                                                    bufferobj);
+                                                    bufferobj,
+                                                    MAP_INTERNAL);
 
           intel_upload_data(brw, map, ib_size, ib_type_size, &bo, &offset);
           brw->ib.start_vertex_offset = offset / ib_type_size;
 
-          ctx->Driver.UnmapBuffer(ctx, bufferobj);
+          ctx->Driver.UnmapBuffer(ctx, bufferobj, MAP_INTERNAL);
        } else {
 	  /* Use CMD_3D_PRIM's start_vertex_offset to avoid re-uploading
 	   * the index buffer state when we're just moving the start index