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, 10 insertions, 5 deletions

diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
index 253a386c271..9814552eb96 100644
--- a/src/mesa/main/bufferobj.h
+++ b/src/mesa/main/bufferobj.h
@@ -37,19 +37,21 @@
  */
 
 
-/** Is the given buffer object currently mapped? */
+/** Is the given buffer object currently mapped by the GL user? */
 static inline GLboolean
-_mesa_bufferobj_mapped(const struct gl_buffer_object *obj)
+_mesa_bufferobj_mapped(const struct gl_buffer_object *obj,
+                       gl_map_buffer_index index)
 {
-   return obj->Pointer != NULL;
+   return obj->Mappings[index].Pointer != NULL;
 }
 
 /** Can we not use this buffer while mapped? */
 static inline GLboolean
 _mesa_check_disallowed_mapping(const struct gl_buffer_object *obj)
 {
-   return _mesa_bufferobj_mapped(obj) &&
-          !(obj->AccessFlags & GL_MAP_PERSISTENT_BIT);
+   return _mesa_bufferobj_mapped(obj, MAP_USER) &&
+          !(obj->Mappings[MAP_USER].AccessFlags &
+            GL_MAP_PERSISTENT_BIT);
 }
 
 /**
@@ -109,6 +111,9 @@ _mesa_total_buffer_object_memory(struct gl_context *ctx);
 extern void
 _mesa_init_buffer_object_functions(struct dd_function_table *driver);
 
+extern void
+_mesa_buffer_unmap_all_mappings(struct gl_context *ctx,
+                                struct gl_buffer_object *bufObj);
 
 /*
  * API functions