On Fri, Aug 27, 2021 at 06:49:11PM +0200, Andreas Gruenbacher wrote: > Turn iov_iter_fault_in_readable into a function that returns the number > of bytes not faulted in (similar to copy_to_user) instead of returning a > non-zero value when any of the requested pages couldn't be faulted in. > This supports the existing users that require all pages to be faulted in > as well as new users that are happy if any pages can be faulted in at > all. > > Rename iov_iter_fault_in_readable to fault_in_iov_iter_readable to make > sure that this change doesn't silently break things. I really disagree with these calling conventions. "Number not faulted in" is bloody useless; make it "nothing could be faulted in"/"something had been faulted in" and it would make sense. Failure several pages into the area should not be treated as a hard error, for one thing, and ANY user of that thing will have to cope with short copies anyway, no matter how much you've managed to fault in.
