On Sat, Dec 11, 2021 at 05:50:51PM +0000, Matthew Wilcox wrote: > On Wed, Dec 08, 2021 at 10:12:03AM +0100, Christoph Hellwig wrote: > > bytes also hold the return value from iomap_write_end, which can contain > > a negative error value. As bytes is always less than the page size even > > the signed type can hold the entire possible range. > > iomap_write_end() can't return an errno. I went through and checked as > part of the folio conversion. It actually has two return values -- 0 > on error and 'len' on success. And it can't have an error because > that only occurs if 'copied' is less than 'length'. > > So I think this should actually be: > > - bytes = iomap_write_end(iter, pos, bytes, bytes, folio); > - if (bytes < 0) > - return bytes; > + status = iomap_write_end(iter, pos, bytes, bytes, folio); > + if (WARN_ON_ONCE(status == 0)) > + return -EIO; > > just like its counterpart loop in iomap_unshare_iter() > > (ok this won't apply to Dan's tree, but YKWIM) Indeed. It might make sense to eventually switch to actually return an errno or a bool as the current calling convention is rather confusing.
