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)
