On 2021-09-29 5:36 p.m., Jason Gunthorpe wrote: > On Wed, Sep 29, 2021 at 05:28:38PM -0600, Logan Gunthorpe wrote: >> >> >> On 2021-09-29 5:21 p.m., Jason Gunthorpe wrote: >>> On Wed, Sep 29, 2021 at 03:50:02PM -0600, Logan Gunthorpe wrote: >>>> >>>> >>>> On 2021-09-28 2:02 p.m., Jason Gunthorpe wrote: >>>>> On Thu, Sep 16, 2021 at 05:40:40PM -0600, Logan Gunthorpe wrote: >>>>>> Hi, >>>>>> >>>>>> This patchset continues my work to add userspace P2PDMA access using >>>>>> O_DIRECT NVMe devices. My last posting[1] just included the first 13 >>>>>> patches in this series, but the early P2PDMA cleanup and map_sg error >>>>>> changes from that series have been merged into v5.15-rc1. To address >>>>>> concerns that that series did not add any new functionality, I've added >>>>>> back the userspcae functionality from the original RFC[2] (but improved >>>>>> based on the original feedback). >>>>> >>>>> I really think this is the best series yet, it really looks nice >>>>> overall. I know the sg flag was a bit of a debate at the start, but it >>>>> serves an undeniable purpose and the resulting standard DMA APIs 'just >>>>> working' is really clean. >>>> >>>> Actually, so far, nobody has said anything negative about using the SG flag. >>>> >>>>> There is more possible here, we could also pass the new GUP flag in the >>>>> ib_umem code.. >>>> >>>> Yes, that would be very useful. >>> >>> You might actually prefer to do that then the bio changes to get the >>> infrastructur merged as it seems less "core" >> >> I'm a little bit more concerned about my patch set growing too large. >> It's already at 20 patches and I think I'll need to add a couple more >> based on the feedback you've already provided. So I'm leaning toward >> pushing more functionality as future work. > > I mean you could postpone the three block related patches and use a > single ib_umem patch instead as the consumer. I think that's not a very compelling use case given the only provider of these VMAs is an NVMe block device. My patch set enables a real world use (copying data between NVMe devices P2P through the CMB with O_DIRECT). Being able to read or write a CMB with RDMA and only RDMA is not very compelling. Logan
