Re: [PATCH v3 00/20] Userspace P2PDMA with O_DIRECT NVMe devices

[Jason Gunthorpe]

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"

Jason