On Tue, Feb 14, 2023 at 07:32:29PM -0500, Peter Xu wrote: > On Tue, Feb 14, 2023 at 02:37:51PM -0800, Axel Rasmussen wrote: > > Agreed, it would likely be a nice cleanup. Peter, any objections? I > > wouldn't mind writing a commit to do this sort of refactor, and rebase > > my change on top of that. > > No objection here. Personally I actually prefer keeping the parameters > around if possible because it's straightforward and no thinking of any > possible indirect accesses all over the place. But maybe growing as long as > 8 is still a moot point.. It's just that I don't really know whether it'll > look that good if we put everything into a struct*. > > Things like src_start/dst_start/.. do not look good to be there: each layer > could loop over its own range of start/end/... so even if not in the > function parameter we'll need a variable to hold them anyway. > > But I do see a few low hanging fruits: > > - I don't see why we need to pass over mmap_changing over all of the > __mcopy_atomic() callers. One chance is we simply pass in the ctx* to > replace "dst_mm + mmap_changing". Now ctx* is completely private to fs/userfaultfd.c and I think it'd be better to keep it this way. > - Merge mcopy_atomic_mode and mode, having last 2 bits for the existing > three modes, then bit 3 for WP, good enough to set it for the new case. Agree, having flags instead of an enum and bools sounds better to me. > - Optionally, we can avoid passing over dst_mm/src_mm all around, when > dst_vma/src_vma is there? +1 > How about we start from simple? > > -- > Peter Xu > -- Sincerely yours, Mike.
