On 5/16/23 2:25?AM, David Hildenbrand wrote: > On 15.05.23 21:55, Jens Axboe wrote: >> On 5/14/23 3:26?PM, Lorenzo Stoakes wrote: >>> Now that the GUP explicitly checks FOLL_LONGTERM pin_user_pages() for >>> broken file-backed mappings in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast >>> writing to file-backed mappings", there is no need to explicitly check VMAs >>> for this condition, so simply remove this logic from io_uring altogether. >> >> Don't have the prerequisite patch handy (not in mainline yet), but if it >> just moves the check, then: >> >> Reviewed-by: Jens Axboe <axboe@xxxxxxxxx> >> > > Jens, please see my note regarding iouring: > > https://lore.kernel.org/bpf/6e96358e-bcb5-cc36-18c3-ec5153867b9a@xxxxxxxxxx/ > > With this patch, MAP_PRIVATE will work as expected (2), but there will > be a change in return code handling (1) that we might have to document > in the man page. I think documenting that newer kernels will return -EFAULT rather than -EOPNOTSUPP should be fine. It's not a new failure case, just a different error value for an already failing case. Should be fine with just a doc update. Will do that now. -- Jens Axboe
