On 2021-09-28 2:02 p.m., Jason Gunthorpe wrote:

On Thu, Sep 16, 2021 at 05:40:40PM -0600, Logan Gunthorpe wrote:

quoted

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.

After this gets merged I would make a series to split out the CMD
genalloc related stuff and try and probably get something like VFIO to
export this kind of memory as well, then it would have pretty nice
coverage.

Yup!

Thanks for the review. Anything I didn't respond to I've either made
changes for, or am still working on and will be addressed for subsequent
postings.

Logan