Re: [PATCH 0/8] dma-mapping: migrate to physical address-based API
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2025-07-08 12:56:28
Also in:
linux-doc, linux-iommu, linux-mm, linux-trace-kernel, lkml, virtualization
On 08.07.2025 14:06, Leon Romanovsky wrote:
On Tue, Jul 08, 2025 at 01:45:20PM +0200, Marek Szyprowski wrote:quoted
On 08.07.2025 13:00, Leon Romanovsky wrote:quoted
On Tue, Jul 08, 2025 at 12:27:09PM +0200, Marek Szyprowski wrote:quoted
On 30.06.2025 15:38, Christoph Hellwig wrote:quoted
On Fri, Jun 27, 2025 at 08:02:13PM +0300, Leon Romanovsky wrote:quoted
quoted
Thanks for this rework! I assume that the next step is to add map_phys callback also to the dma_map_ops and teach various dma-mapping providers to use it to avoid more phys-to-page-to-phys conversions.Probably Christoph will say yes, however I personally don't see any benefit in this. Maybe I wrong here, but all existing .map_page() implementation platforms don't support p2p anyway. They won't benefit from this such conversion.I think that conversion should eventually happen, and rather sooner than later.Agreed. Applied patches 1-7 to my dma-mapping-next branch. Let me know if one needs a stable branch with it.Thanks a lot, I don't think that stable branch is needed. Realistically speaking, my VFIO DMA work won't be merged this cycle, We are in -rc5, it is complete rewrite from RFC version and touches pci-p2p code (to remove dependency on struct page) in addition to VFIO, so it will take time. Regarding, last patch (hmm), it will be great if you can take it. We didn't touch anything in hmm.c this cycle and have no plans to send PR. It can safely go through your tree.Okay, then I would like to get an explicit ack from Jérôme for this.Jerome is not active in HMM world for a long time already. HMM tree is managed by us (RDMA) https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git/log/?h=hmm ➜ kernel git:(m/dmabuf-vfio) git log --merges mm/hmm.c ... Pull HMM updates from Jason Gunthorpe: ... https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=58ba80c4740212c29a1cf9b48f588e60a7612209 +hmm git git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git#hmm We just never bothered to reflect current situation in MAINTAINERS file.
Maybe this is the time to update it :) I was just a bit confused that no-one commented the HMM patch, but if You maintain it, then this is okay. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland