Messages in this thread | | | From | Jason Gunthorpe <> | Subject | Re: [PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk | Date | Thu, 15 Aug 2019 20:41:33 +0000 |
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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
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