Re: [PATCH 1/3] mm: Add unsafe_follow_pfn

2021-03-29 Thread Jason Gunthorpe
On Tue, Mar 16, 2021 at 04:33:01PM +0100, Daniel Vetter wrote: > Way back it was a reasonable assumptions that iomem mappings never > change the pfn range they point at. But this has changed: > > - gpu drivers dynamically manage their memory nowadays, invalidating > ptes with unmap_mapping_range w

[PATCH 1/3] mm: Add unsafe_follow_pfn

2021-03-16 Thread Daniel Vetter
Way back it was a reasonable assumptions that iomem mappings never change the pfn range they point at. But this has changed: - gpu drivers dynamically manage their memory nowadays, invalidating ptes with unmap_mapping_range when buffers get moved - contiguous dma allocations have moved from dedic