On Thu, Aug 15, 2019 at 04:33:06PM -0400, Jerome Glisse wrote: > So nor HMM nor driver should dereference the struct page (i do not > think any iommu driver would either), Er, they do technically deref the struct page: nouveau_dmem_convert_pfn(struct nouveau_drm *drm, struct hmm_range *range) struct page *page; page = hmm_pfn_to_page(range, range->pfns[i]); if (!nouveau_dmem_page(drm, page)) { nouveau_dmem_page(struct nouveau_drm *drm, struct page *page) { return is_device_private_page(page) && drm->dmem == page_to_dmem(page) Which does touch 'page->pgmap' Is this OK without having a get_dev_pagemap() ? Noting that the collision-retry scheme doesn't protect anything here as we can have a concurrent invalidation while doing the above deref. Jason _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel