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]>

10 files changed, 168 insertions, 144 deletions

diff --git a/src/mesa/drivers/dri/i915/intel_buffer_objects.c b/src/mesa/drivers/dri/i915/intel_buffer_objects.c
index f4fb9998cde..b93dd20ed01 100644
--- a/src/mesa/drivers/dri/i915/intel_buffer_objects.c
+++ b/src/mesa/drivers/dri/i915/intel_buffer_objects.c
@@ -40,7 +40,8 @@
 #include "intel_regions.h"
 
 static GLboolean
-intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj);
+intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj,
+                      gl_map_buffer_index index);
 
 /** Allocates a new drm_intel_bo to store the data for the buffer object. */
 static void
@@ -93,8 +94,7 @@ intel_bufferobj_free(struct gl_context * ctx, struct gl_buffer_object *obj)
     * to the spec, but Mesa doesn't do UnmapBuffer for us at context destroy
     * (though it does if you call glDeleteBuffers)
     */
-   if (obj->Pointer)
-      intel_bufferobj_unmap(ctx, obj);
+   _mesa_buffer_unmap_all_mappings(ctx, obj);
 
    free(intel_obj->sys_buffer);
 
@@ -127,7 +127,8 @@ intel_bufferobj_data(struct gl_context * ctx,
    intel_obj->Base.Usage = usage;
    intel_obj->Base.StorageFlags = storageFlags;
 
-   assert(!obj->Pointer); /* Mesa should have unmapped it */
+   assert(!obj->Mappings[MAP_USER].Pointer); /* Mesa should have unmapped it */
+   assert(!obj->Mappings[MAP_INTERNAL].Pointer);
 
    if (intel_obj->buffer != NULL)
       release_buffer(intel_obj);
@@ -272,7 +273,8 @@ intel_bufferobj_get_subdata(struct gl_context * ctx,
 static void *
 intel_bufferobj_map_range(struct gl_context * ctx,
 			  GLintptr offset, GLsizeiptr length,
-			  GLbitfield access, struct gl_buffer_object *obj)
+			  GLbitfield access, struct gl_buffer_object *obj,
+                          gl_map_buffer_index index)
 {
    struct intel_context *intel = intel_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
@@ -282,9 +284,9 @@ intel_bufferobj_map_range(struct gl_context * ctx,
    /* _mesa_MapBufferRange (GL entrypoint) sets these, but the vbo module also
     * internally uses our functions directly.
     */
-   obj->Offset = offset;
-   obj->Length = length;
-   obj->AccessFlags = access;
+   obj->Mappings[index].Offset = offset;
+   obj->Mappings[index].Length = length;
+   obj->Mappings[index].AccessFlags = access;
 
    if (intel_obj->sys_buffer) {
       const bool read_only =
@@ -294,8 +296,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
 	 release_buffer(intel_obj);
 
       if (!intel_obj->buffer || intel_obj->source) {
-	 obj->Pointer = intel_obj->sys_buffer + offset;
-	 return obj->Pointer;
+	 obj->Mappings[index].Pointer = intel_obj->sys_buffer + offset;
+	 return obj->Mappings[index].Pointer;
       }
 
       free(intel_obj->sys_buffer);
@@ -303,7 +305,7 @@ intel_bufferobj_map_range(struct gl_context * ctx,
    }
 
    if (intel_obj->buffer == NULL) {
-      obj->Pointer = NULL;
+      obj->Mappings[index].Pointer = NULL;
       return NULL;
    }
 
@@ -346,23 +348,25 @@ intel_bufferobj_map_range(struct gl_context * ctx,
       const unsigned extra = (uintptr_t) offset % alignment;
 
       if (access & GL_MAP_FLUSH_EXPLICIT_BIT) {
-         intel_obj->range_map_buffer = _mesa_align_malloc(length + extra,
-                                                          alignment);
-         obj->Pointer = intel_obj->range_map_buffer + extra;
+         intel_obj->range_map_buffer[index] =
+            _mesa_align_malloc(length + extra, alignment);
+         obj->Mappings[index].Pointer =
+            intel_obj->range_map_buffer[index] + extra;
       } else {
-	 intel_obj->range_map_bo = drm_intel_bo_alloc(intel->bufmgr,
-						      "range map",
-                                                      length + extra,
-                                                      alignment);
+	 intel_obj->range_map_bo[index] = drm_intel_bo_alloc(intel->bufmgr,
+                                                             "range map",
+                                                             length + extra,
+                                                             alignment);
 	 if (!(access & GL_MAP_READ_BIT)) {
-	    drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo);
+	    drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo[index]);
 	 } else {
-	    drm_intel_bo_map(intel_obj->range_map_bo,
+	    drm_intel_bo_map(intel_obj->range_map_bo[index],
 			     (access & GL_MAP_WRITE_BIT) != 0);
 	 }
-	 obj->Pointer = intel_obj->range_map_bo->virtual + extra;
+	 obj->Mappings[index].Pointer =
+            intel_obj->range_map_bo[index]->virtual + extra;
       }
-      return obj->Pointer;
+      return obj->Mappings[index].Pointer;
    }
 
    if (access & GL_MAP_UNSYNCHRONIZED_BIT)
@@ -373,8 +377,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
       drm_intel_bo_map(intel_obj->buffer, (access & GL_MAP_WRITE_BIT) != 0);
    }
 
-   obj->Pointer = intel_obj->buffer->virtual + offset;
-   return obj->Pointer;
+   obj->Mappings[index].Pointer = intel_obj->buffer->virtual + offset;
+   return obj->Mappings[index].Pointer;
 }
 
 /* Ideally we'd use a BO to avoid taking up cache space for the temporary
@@ -385,7 +389,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
 static void
 intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
 				   GLintptr offset, GLsizeiptr length,
-				   struct gl_buffer_object *obj)
+                                   struct gl_buffer_object *obj,
+                                   gl_map_buffer_index index)
 {
    struct intel_context *intel = intel_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
@@ -394,7 +399,7 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
    /* Unless we're in the range map using a temporary system buffer,
     * there's no work to do.
     */
-   if (intel_obj->range_map_buffer == NULL)
+   if (intel_obj->range_map_buffer[index] == NULL)
       return;
 
    if (length == 0)
@@ -406,10 +411,11 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
     * former points to the actual mapping while the latter may be offset to
     * meet alignment guarantees.
     */
-   drm_intel_bo_subdata(temp_bo, 0, length, obj->Pointer);
+   drm_intel_bo_subdata(temp_bo, 0, length, obj->Mappings[index].Pointer);
 
    intel_emit_linear_blit(intel,
-			  intel_obj->buffer, obj->Offset + offset,
+			  intel_obj->buffer,
+                          obj->Mappings[index].Offset + offset,
 			  temp_bo, 0,
 			  length);
 
@@ -421,33 +427,35 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
  * Called via glUnmapBuffer().
  */
 static GLboolean
-intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj)
+intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj,
+                      gl_map_buffer_index index)
 {
    struct intel_context *intel = intel_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
 
    assert(intel_obj);
-   assert(obj->Pointer);
+   assert(obj->Mappings[index].Pointer);
    if (intel_obj->sys_buffer != NULL) {
       /* always keep the mapping around. */
-   } else if (intel_obj->range_map_buffer != NULL) {
+   } else if (intel_obj->range_map_buffer[index] != NULL) {
       /* Since we've emitted some blits to buffers that will (likely) be used
        * in rendering operations in other cache domains in this batch, emit a
        * flush.  Once again, we wish for a domain tracker in libdrm to cover
        * usage inside of a batchbuffer.
        */
       intel_batchbuffer_emit_mi_flush(intel);
-      _mesa_align_free(intel_obj->range_map_buffer);
-      intel_obj->range_map_buffer = NULL;
-   } else if (intel_obj->range_map_bo != NULL) {
-      const unsigned extra = obj->Pointer - intel_obj->range_map_bo->virtual;
+      _mesa_align_free(intel_obj->range_map_buffer[index]);
+      intel_obj->range_map_buffer[index] = NULL;
+   } else if (intel_obj->range_map_bo[index] != NULL) {
+      const unsigned extra = obj->Mappings[index].Pointer -
+                             intel_obj->range_map_bo[index]->virtual;
 
-      drm_intel_bo_unmap(intel_obj->range_map_bo);
+      drm_intel_bo_unmap(intel_obj->range_map_bo[index]);
 
       intel_emit_linear_blit(intel,
-			     intel_obj->buffer, obj->Offset,
-			     intel_obj->range_map_bo, extra,
-			     obj->Length);
+			     intel_obj->buffer, obj->Mappings[index].Offset,
+			     intel_obj->range_map_bo[index], extra,
+			     obj->Mappings[index].Length);
 
       /* Since we've emitted some blits to buffers that will (likely) be used
        * in rendering operations in other cache domains in this batch, emit a
@@ -456,14 +464,14 @@ intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj)
        */
       intel_batchbuffer_emit_mi_flush(intel);
 
-      drm_intel_bo_unreference(intel_obj->range_map_bo);
-      intel_obj->range_map_bo = NULL;
+      drm_intel_bo_unreference(intel_obj->range_map_bo[index]);
+      intel_obj->range_map_bo[index] = NULL;
    } else if (intel_obj->buffer != NULL) {
       drm_intel_bo_unmap(intel_obj->buffer);
    }
-   obj->Pointer = NULL;
-   obj->Offset = 0;
-   obj->Length = 0;
+   obj->Mappings[index].Pointer = NULL;
+   obj->Mappings[index].Offset = 0;
+   obj->Mappings[index].Length = 0;
 
    return true;
 }
@@ -607,22 +615,24 @@ intel_bufferobj_copy_subdata(struct gl_context *ctx,
 	 char *ptr = intel_bufferobj_map_range(ctx, 0, dst->Size,
 					       GL_MAP_READ_BIT |
 					       GL_MAP_WRITE_BIT,
-					       dst);
+					       dst, MAP_INTERNAL);
 	 memmove(ptr + write_offset, ptr + read_offset, size);
-	 intel_bufferobj_unmap(ctx, dst);
+	 intel_bufferobj_unmap(ctx, dst, MAP_INTERNAL);
       } else {
 	 const char *src_ptr;
 	 char *dst_ptr;
 
 	 src_ptr =  intel_bufferobj_map_range(ctx, 0, src->Size,
-					      GL_MAP_READ_BIT, src);
+					      GL_MAP_READ_BIT, src,
+                                              MAP_INTERNAL);
 	 dst_ptr =  intel_bufferobj_map_range(ctx, 0, dst->Size,
-					      GL_MAP_WRITE_BIT, dst);
+					      GL_MAP_WRITE_BIT, dst,
+                                              MAP_INTERNAL);
 
 	 memcpy(dst_ptr + write_offset, src_ptr + read_offset, size);
 
-	 intel_bufferobj_unmap(ctx, src);
-	 intel_bufferobj_unmap(ctx, dst);
+	 intel_bufferobj_unmap(ctx, src, MAP_INTERNAL);
+	 intel_bufferobj_unmap(ctx, dst, MAP_INTERNAL);
       }
       return;
    }
diff --git a/src/mesa/drivers/dri/i915/intel_buffer_objects.h b/src/mesa/drivers/dri/i915/intel_buffer_objects.h
index d2671f98c45..9ebfe4844e7 100644
--- a/src/mesa/drivers/dri/i915/intel_buffer_objects.h
+++ b/src/mesa/drivers/dri/i915/intel_buffer_objects.h
@@ -46,10 +46,8 @@ struct intel_buffer_object
    /** System memory buffer data, if not using a BO to store the data. */
    void *sys_buffer;
 
-   drm_intel_bo *range_map_bo;
-   void *range_map_buffer;
-   unsigned int range_map_offset;
-   GLsizei range_map_size;
+   drm_intel_bo *range_map_bo[MAP_COUNT];
+   void *range_map_buffer[MAP_COUNT];
 
    bool source;
 };
diff --git a/src/mesa/drivers/dri/i915/intel_pixel_bitmap.c b/src/mesa/drivers/dri/i915/intel_pixel_bitmap.c
index f4a2293e6da..ce8ea4c07b3 100644
--- a/src/mesa/drivers/dri/i915/intel_pixel_bitmap.c
+++ b/src/mesa/drivers/dri/i915/intel_pixel_bitmap.c
@@ -78,7 +78,8 @@ static const GLubyte *map_pbo( struct gl_context *ctx,
 
    buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0, unpack->BufferObj->Size,
 						GL_MAP_READ_BIT,
-						unpack->BufferObj);
+						unpack->BufferObj,
+                                                MAP_INTERNAL);
    if (!buf) {
       _mesa_error(ctx, GL_INVALID_OPERATION, "glBitmap(PBO is mapped)");
       return NULL;
@@ -311,7 +312,7 @@ out:
 
    if (_mesa_is_bufferobj(unpack->BufferObj)) {
       /* done with PBO so unmap it now */
-      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
    }
 
    intel_check_front_buffer_rendering(intel);
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
diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.c b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
index c92ca2fcafe..bd7e88d8762 100644
--- a/src/mesa/drivers/dri/i965/intel_buffer_objects.c
+++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
@@ -82,7 +82,8 @@ brw_bo_map_gtt(struct brw_context *brw, drm_intel_bo *bo, const char *bo_name)
 }
 
 static GLboolean
-intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj);
+intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj,
+                      gl_map_buffer_index index);
 
 static void
 intel_bufferobj_mark_gpu_usage(struct intel_buffer_object *intel_obj,
@@ -159,8 +160,7 @@ intel_bufferobj_free(struct gl_context * ctx, struct gl_buffer_object *obj)
     * to the spec, but Mesa doesn't do UnmapBuffer for us at context destroy
     * (though it does if you call glDeleteBuffers)
     */
-   if (obj->Pointer)
-      intel_bufferobj_unmap(ctx, obj);
+   _mesa_buffer_unmap_all_mappings(ctx, obj);
 
    drm_intel_bo_unreference(intel_obj->buffer);
    free(intel_obj);
@@ -197,7 +197,8 @@ intel_bufferobj_data(struct gl_context * ctx,
    intel_obj->Base.Usage = usage;
    intel_obj->Base.StorageFlags = storageFlags;
 
-   assert(!obj->Pointer); /* Mesa should have unmapped it */
+   assert(!obj->Mappings[MAP_USER].Pointer); /* Mesa should have unmapped it */
+   assert(!obj->Mappings[MAP_INTERNAL].Pointer);
 
    if (intel_obj->buffer != NULL)
       release_buffer(intel_obj);
@@ -351,7 +352,8 @@ intel_bufferobj_get_subdata(struct gl_context * ctx,
 static void *
 intel_bufferobj_map_range(struct gl_context * ctx,
 			  GLintptr offset, GLsizeiptr length,
-			  GLbitfield access, struct gl_buffer_object *obj)
+			  GLbitfield access, struct gl_buffer_object *obj,
+                          gl_map_buffer_index index)
 {
    struct brw_context *brw = brw_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
@@ -361,12 +363,12 @@ intel_bufferobj_map_range(struct gl_context * ctx,
    /* _mesa_MapBufferRange (GL entrypoint) sets these, but the vbo module also
     * internally uses our functions directly.
     */
-   obj->Offset = offset;
-   obj->Length = length;
-   obj->AccessFlags = access;
+   obj->Mappings[index].Offset = offset;
+   obj->Mappings[index].Length = length;
+   obj->Mappings[index].AccessFlags = access;
 
    if (intel_obj->buffer == NULL) {
-      obj->Pointer = NULL;
+      obj->Mappings[index].Pointer = NULL;
       return NULL;
    }
 
@@ -410,23 +412,25 @@ intel_bufferobj_map_range(struct gl_context * ctx,
       const unsigned extra = (uintptr_t) offset % alignment;
 
       if (access & GL_MAP_FLUSH_EXPLICIT_BIT) {
-         intel_obj->range_map_buffer = _mesa_align_malloc(length + extra,
-                                                          alignment);
-         obj->Pointer = intel_obj->range_map_buffer + extra;
+         intel_obj->range_map_buffer[index] = _mesa_align_malloc(length + extra,
+                                                                 alignment);
+         obj->Mappings[index].Pointer =
+            intel_obj->range_map_buffer[index] + extra;
       } else {
-	 intel_obj->range_map_bo = drm_intel_bo_alloc(brw->bufmgr,
-						      "range map",
-                                                      length + extra,
-                                                      alignment);
+	 intel_obj->range_map_bo[index] = drm_intel_bo_alloc(brw->bufmgr,
+                                                             "range map",
+                                                             length + extra,
+                                                             alignment);
 	 if (!(access & GL_MAP_READ_BIT)) {
-	    drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo);
+	    drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo[index]);
 	 } else {
-	    drm_intel_bo_map(intel_obj->range_map_bo,
+	    drm_intel_bo_map(intel_obj->range_map_bo[index],
 			     (access & GL_MAP_WRITE_BIT) != 0);
 	 }
-	 obj->Pointer = intel_obj->range_map_bo->virtual + extra;
+	 obj->Mappings[index].Pointer =
+            intel_obj->range_map_bo[index]->virtual + extra;
       }
-      return obj->Pointer;
+      return obj->Mappings[index].Pointer;
    }
 
    if (access & GL_MAP_UNSYNCHRONIZED_BIT)
@@ -439,8 +443,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
       intel_bufferobj_mark_inactive(intel_obj);
    }
 
-   obj->Pointer = intel_obj->buffer->virtual + offset;
-   return obj->Pointer;
+   obj->Mappings[index].Pointer = intel_obj->buffer->virtual + offset;
+   return obj->Mappings[index].Pointer;
 }
 
 /**
@@ -459,7 +463,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
 static void
 intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
 				   GLintptr offset, GLsizeiptr length,
-				   struct gl_buffer_object *obj)
+				   struct gl_buffer_object *obj,
+                                   gl_map_buffer_index index)
 {
    struct brw_context *brw = brw_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
@@ -468,7 +473,7 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
    /* Unless we're in the range map using a temporary system buffer,
     * there's no work to do.
     */
-   if (intel_obj->range_map_buffer == NULL)
+   if (intel_obj->range_map_buffer[index] == NULL)
       return;
 
    if (length == 0)
@@ -480,13 +485,16 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
     * former points to the actual mapping while the latter may be offset to
     * meet alignment guarantees.
     */
-   drm_intel_bo_subdata(temp_bo, 0, length, obj->Pointer);
+   drm_intel_bo_subdata(temp_bo, 0, length, obj->Mappings[index].Pointer);
 
    intel_emit_linear_blit(brw,
-			  intel_obj->buffer, obj->Offset + offset,
+			  intel_obj->buffer,
+                          obj->Mappings[index].Offset + offset,
 			  temp_bo, 0,
 			  length);
-   intel_bufferobj_mark_gpu_usage(intel_obj, obj->Offset + offset, length);
+   intel_bufferobj_mark_gpu_usage(intel_obj,
+                                  obj->Mappings[index].Offset + offset,
+                                  length);
 
    drm_intel_bo_unreference(temp_bo);
 }
@@ -498,32 +506,35 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
  * Implements glUnmapBuffer().
  */
 static GLboolean
-intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj)
+intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj,
+                      gl_map_buffer_index index)
 {
    struct brw_context *brw = brw_context(ctx);
    struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
 
    assert(intel_obj);
-   assert(obj->Pointer);
-   if (intel_obj->range_map_buffer != NULL) {
+   assert(obj->Mappings[index].Pointer);
+   if (intel_obj->range_map_buffer[index] != NULL) {
       /* Since we've emitted some blits to buffers that will (likely) be used
        * in rendering operations in other cache domains in this batch, emit a
        * flush.  Once again, we wish for a domain tracker in libdrm to cover
        * usage inside of a batchbuffer.
        */
       intel_batchbuffer_emit_mi_flush(brw);
-      _mesa_align_free(intel_obj->range_map_buffer);
-      intel_obj->range_map_buffer = NULL;
+      _mesa_align_free(intel_obj->range_map_buffer[index]);
+      intel_obj->range_map_buffer[index] = NULL;
    } else if (intel_obj->range_map_bo != NULL) {
-      const unsigned extra = obj->Pointer - intel_obj->range_map_bo->virtual;
+      const unsigned extra = obj->Mappings[index].Pointer -
+                             intel_obj->range_map_bo[index]->virtual;
 
-      drm_intel_bo_unmap(intel_obj->range_map_bo);
+      drm_intel_bo_unmap(intel_obj->range_map_bo[index]);
 
       intel_emit_linear_blit(brw,
-			     intel_obj->buffer, obj->Offset,
-			     intel_obj->range_map_bo, extra,
-			     obj->Length);
-      intel_bufferobj_mark_gpu_usage(intel_obj, obj->Offset, obj->Length);
+			     intel_obj->buffer, obj->Mappings[index].Offset,
+			     intel_obj->range_map_bo[index], extra,
+			     obj->Mappings[index].Length);
+      intel_bufferobj_mark_gpu_usage(intel_obj, obj->Mappings[index].Offset,
+                                     obj->Mappings[index].Length);
 
       /* Since we've emitted some blits to buffers that will (likely) be used
        * in rendering operations in other cache domains in this batch, emit a
@@ -532,14 +543,14 @@ intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj)
        */
       intel_batchbuffer_emit_mi_flush(brw);
 
-      drm_intel_bo_unreference(intel_obj->range_map_bo);
-      intel_obj->range_map_bo = NULL;
+      drm_intel_bo_unreference(intel_obj->range_map_bo[index]);
+      intel_obj->range_map_bo[index] = NULL;
    } else if (intel_obj->buffer != NULL) {
       drm_intel_bo_unmap(intel_obj->buffer);
    }
-   obj->Pointer = NULL;
-   obj->Offset = 0;
-   obj->Length = 0;
+   obj->Mappings[index].Pointer = NULL;
+   obj->Mappings[index].Offset = 0;
+   obj->Mappings[index].Length = 0;
 
    return true;
 }
diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.h b/src/mesa/drivers/dri/i965/intel_buffer_objects.h
index 3b6d8352702..2197707c8cc 100644
--- a/src/mesa/drivers/dri/i965/intel_buffer_objects.h
+++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.h
@@ -42,9 +42,8 @@ struct intel_buffer_object
    struct gl_buffer_object Base;
    drm_intel_bo *buffer;     /* the low-level buffer manager's buffer handle */
 
-   drm_intel_bo *range_map_bo;
-   void *range_map_buffer;
-   unsigned int range_map_offset;
+   drm_intel_bo *range_map_bo[MAP_COUNT];
+   void *range_map_buffer[MAP_COUNT];
 
    /** @{
     * Tracking for what range of the BO may currently be in use by the GPU.
diff --git a/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c b/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
index a9674ca2db3..49a9bed1921 100644
--- a/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
+++ b/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
@@ -79,7 +79,8 @@ static const GLubyte *map_pbo( struct gl_context *ctx,
 
    buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0, unpack->BufferObj->Size,
 						GL_MAP_READ_BIT,
-						unpack->BufferObj);
+						unpack->BufferObj,
+                                                MAP_INTERNAL);
    if (!buf) {
       _mesa_error(ctx, GL_INVALID_OPERATION, "glBitmap(PBO is mapped)");
       return NULL;
@@ -317,7 +318,7 @@ out:
 
    if (_mesa_is_bufferobj(unpack->BufferObj)) {
       /* done with PBO so unmap it now */
-      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
    }
 
    intel_check_front_buffer_rendering(brw);
diff --git a/src/mesa/drivers/dri/nouveau/nouveau_bufferobj.c b/src/mesa/drivers/dri/nouveau/nouveau_bufferobj.c
index 783a152955f..9a3d41739b9 100644
--- a/src/mesa/drivers/dri/nouveau/nouveau_bufferobj.c
+++ b/src/mesa/drivers/dri/nouveau/nouveau_bufferobj.c
@@ -127,12 +127,13 @@ nouveau_bufferobj_get_subdata(struct gl_context *ctx, GLintptrARB offset,
 static void *
 nouveau_bufferobj_map_range(struct gl_context *ctx, GLintptr offset,
 			    GLsizeiptr length, GLbitfield access,
-			    struct gl_buffer_object *obj)
+			    struct gl_buffer_object *obj,
+                            gl_map_buffer_index index)
 {
 	unsigned flags = 0;
 	char *map;
 
-	assert(!obj->Pointer);
+	assert(!obj->Mappings[index].Pointer);
 
 	if (!(access & GL_MAP_UNSYNCHRONIZED_BIT)) {
 		if (access & GL_MAP_READ_BIT)
@@ -145,23 +146,24 @@ nouveau_bufferobj_map_range(struct gl_context *ctx, GLintptr offset,
 	if (!map)
 		return NULL;
 
-	obj->Pointer = map + offset;
-	obj->Offset = offset;
-	obj->Length = length;
-	obj->AccessFlags = access;
+	obj->Mappings[index].Pointer = map + offset;
+	obj->Mappings[index].Offset = offset;
+	obj->Mappings[index].Length = length;
+	obj->Mappings[index].AccessFlags = access;
 
-	return obj->Pointer;
+	return obj->Mappings[index].Pointer;
 }
 
 static GLboolean
-nouveau_bufferobj_unmap(struct gl_context *ctx, struct gl_buffer_object *obj)
+nouveau_bufferobj_unmap(struct gl_context *ctx, struct gl_buffer_object *obj,
+                        gl_map_buffer_index index)
 {
-	assert(obj->Pointer);
+	assert(obj->Mappings[index].Pointer);
 
-	obj->Pointer = NULL;
-	obj->Offset = 0;
-	obj->Length = 0;
-	obj->AccessFlags = 0;
+	obj->Mappings[index].Pointer = NULL;
+	obj->Mappings[index].Offset = 0;
+	obj->Mappings[index].Length = 0;
+	obj->Mappings[index].AccessFlags = 0;
 
 	return GL_TRUE;
 }
diff --git a/src/mesa/drivers/dri/radeon/radeon_buffer_objects.c b/src/mesa/drivers/dri/radeon/radeon_buffer_objects.c
index 7663178d63d..6294dbe1f98 100644
--- a/src/mesa/drivers/dri/radeon/radeon_buffer_objects.c
+++ b/src/mesa/drivers/dri/radeon/radeon_buffer_objects.c
@@ -60,9 +60,12 @@ radeonDeleteBufferObject(struct gl_context * ctx,
                          struct gl_buffer_object *obj)
 {
     struct radeon_buffer_object *radeon_obj = get_radeon_buffer_object(obj);
+    int i;
 
-    if (obj->Pointer) {
-        radeon_bo_unmap(radeon_obj->bo);
+    for (i = 0; i < MAP_COUNT; i++) {
+       if (obj->Mappings[i].Pointer) {
+           radeon_bo_unmap(radeon_obj->bo);
+       }
     }
 
     if (radeon_obj->bo) {
@@ -175,7 +178,8 @@ radeonGetBufferSubData(struct gl_context * ctx,
 static void *
 radeonMapBufferRange(struct gl_context * ctx,
 		     GLintptr offset, GLsizeiptr length,
-		     GLbitfield access, struct gl_buffer_object *obj)
+		     GLbitfield access, struct gl_buffer_object *obj,
+                     gl_map_buffer_index index)
 {
     struct radeon_buffer_object *radeon_obj = get_radeon_buffer_object(obj);
     const GLboolean write_only =
@@ -186,18 +190,18 @@ radeonMapBufferRange(struct gl_context * ctx,
     }
 
     if (radeon_obj->bo == NULL) {
-        obj->Pointer = NULL;
+        obj->Mappings[index].Pointer = NULL;
         return NULL;
     }
 
-    obj->Offset = offset;
-    obj->Length = length;
-    obj->AccessFlags = access;
+    obj->Mappings[index].Offset = offset;
+    obj->Mappings[index].Length = length;
+    obj->Mappings[index].AccessFlags = access;
 
     radeon_bo_map(radeon_obj->bo, write_only);
 
-    obj->Pointer = radeon_obj->bo->ptr + offset;
-    return obj->Pointer;
+    obj->Mappings[index].Pointer = radeon_obj->bo->ptr + offset;
+    return obj->Mappings[index].Pointer;
 }
 
 
@@ -206,7 +210,8 @@ radeonMapBufferRange(struct gl_context * ctx,
  */
 static GLboolean
 radeonUnmapBuffer(struct gl_context * ctx,
-                  struct gl_buffer_object *obj)
+                  struct gl_buffer_object *obj,
+                  gl_map_buffer_index index)
 {
     struct radeon_buffer_object *radeon_obj = get_radeon_buffer_object(obj);
 
@@ -214,9 +219,9 @@ radeonUnmapBuffer(struct gl_context * ctx,
         radeon_bo_unmap(radeon_obj->bo);
     }
 
-    obj->Pointer = NULL;
-    obj->Offset = 0;
-    obj->Length = 0;
+    obj->Mappings[index].Pointer = NULL;
+    obj->Mappings[index].Offset = 0;
+    obj->Mappings[index].Length = 0;
 
     return GL_TRUE;
 }
diff --git a/src/mesa/drivers/x11/xm_dd.c b/src/mesa/drivers/x11/xm_dd.c
index fc0b956743d..c0dcb61e234 100644
--- a/src/mesa/drivers/x11/xm_dd.c
+++ b/src/mesa/drivers/x11/xm_dd.c
@@ -366,12 +366,10 @@ xmesa_DrawPixels_8R8G8B( struct gl_context *ctx,
          buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0,
 						      unpack->BufferObj->Size,
 						      GL_MAP_READ_BIT,
-						      unpack->BufferObj);
+						      unpack->BufferObj,
+                                                      MAP_INTERNAL);
          if (!buf) {
-            /* buffer is already mapped - that's an error */
-            _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawPixels(PBO is mapped)");
-            return;
+            return; /* error */
          }
          pixels = ADD_POINTERS(buf, pixels);
       }
@@ -417,7 +415,7 @@ xmesa_DrawPixels_8R8G8B( struct gl_context *ctx,
       }
 
       if (_mesa_is_bufferobj(unpack->BufferObj)) {
-         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
       }
    }
    else {
@@ -500,12 +498,10 @@ xmesa_DrawPixels_5R6G5B( struct gl_context *ctx,
          buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0,
 						      unpack->BufferObj->Size,
 						      GL_MAP_READ_BIT,
-						      unpack->BufferObj);
+						      unpack->BufferObj,
+                                                      MAP_INTERNAL);
          if (!buf) {
-            /* buffer is already mapped - that's an error */
-            _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawPixels(PBO is mapped)");
-            return;
+            return; /* error */
          }
          pixels = ADD_POINTERS(buf, pixels);
       }
@@ -550,7 +546,7 @@ xmesa_DrawPixels_5R6G5B( struct gl_context *ctx,
       }
 
       if (unpack->BufferObj->Name) {
-         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
       }
    }
    else {