Hi all, I've been looking at dma_buf_v(un)map, with a goal to standardize locking for at least dynamic dma-buf exporters/importers, most likely by requiring dma_resv_lock. And I got questions around how this is supposed to work, since a big chunk of drivers seem to entirely lack locking around ttm_bo_kmap. Two big ones: - ttm_bo_kmap looks at bo->mem to figure out what/where to kmap to get at that buffer. bo->mem is supposed to be protected with dma_resv_lock, but at least amgpu/nouveau/radeon/qxl don't grab that in their prime vmap function. - between the vmap and vunmap something needs to make sure the backing storage doesn't move around. I didn't find that either anywhere, ttm_bo_kmap simply seems to set up the mapping, leaving locking and refcounting to callers. - vram helpers have at least locking, but I'm still missing the refcounting. vmwgfx doesn't bother with vmap. What am I missing? Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel