Personally I come at this from the 'I just want my vmas patch series' unblocked
perspective :) and feel there's a functional aspect here too.
I know, it always gets messy when touching such sensible topics :P
I feel that several people owe me drinks at LSF/MM :P
To cut a long story short to your other points, I'm _really_ leaning
towards an opt-in variant of this change that we just hand to io_uring to
make everything simple with minimum risk (if Jens was also open to this
idea, it'd simply be deleting the open coded vma checks there and adding
FOLL_SAFE_FILE_WRITE).
That way we can save the delightful back and forth for another time while
adding a useful feature and documenting the issue.
Altneratively I could try to adapt this to also do the GUP-fast check,
hoping that no FOLL_FAST_ONLY users would get nixed (I'd have to check who
uses that). The others should just get degraded to a standard GUP right?
I feel these various series have really helped beat out some details about
GUP, so as to your point on another thread (trying to reduce noise here
:P), I think discussion at LSF/MM is also a sensible idea, also you know,
if beers were bought too it could all work out nicely :]