On Fri, Aug 20, 2021 at 03:40:08PM +0000, Michael Kelley wrote: > I see that the swiotlb code gets and uses the min_align_mask field. But > the NVME driver is the only driver that ever sets it, so the value is zero > in all other cases. Does swiotlb just use PAGE_SIZE in that that case? I > couldn't tell from a quick glance at the swiotlb code. The encoding isn't all that common. I only know it for the RDMA memory registration format, and RDMA in general does not interact very well with swiotlb (although the in-kernel drivers should work fine, it is userspace RDMA that is the problem). It seems recently a new driver using the format (mpi3mr) also showed up. All these should probably set the min_align_mask.
