On Wed, Sep 3, 2025 at 11:21 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > On Fri, Aug 29, 2025 at 04:56:23PM -0700, Joanne Koong wrote: > > Add a "struct iomap_read_ops" that contains a read_folio_range() > > callback that callers can provide as a custom handler for reading in a > > folio range, if the caller does not wish to issue bio read requests > > (which otherwise is the default behavior). read_folio_range() may read > > the request asynchronously or synchronously. The caller is responsible > > for calling iomap_start_folio_read()/iomap_finish_folio_read() when > > reading the folio range. > > > > This makes it so that non-block based filesystems may use iomap for > > reads. > > Also for things like checksumming in block based file systems. I've > carried this patch originally from Goldwyn around for a while with > my PI support patches: > > https://git.infradead.org/?p=users/hch/misc.git;a=commitdiff;h=54ad84fded1d954cb9ebf483008cb57421efc959 > > I'll see if we'll still need submit_bio with your version or if > that can be reworked on top of your callout. > > > @@ -356,6 +356,12 @@ void iomap_finish_folio_read(struct folio *folio, size_t off, size_t len, > > if (finished) > > folio_end_read(folio, uptodate); > > } > > + > > +void iomap_finish_folio_read(struct folio *folio, size_t off, size_t len, > > + int error) > > +{ > > + return __iomap_finish_folio_read(folio, off, len, error, true); > > +} > > EXPORT_SYMBOL_GPL(iomap_finish_folio_read); > > .. > > > + if (ifs) > > + iomap_start_folio_read(folio, 1); > > I don't fully understand these changes. Any chance they could be split > into a prep patch with a detailed commit message so that the method > addition itself is mostly mechanical? Good idea, I will do this in v2 to make it more clear. Thanks for looking at the patchset. > > > + if (read_ops && read_ops->read_folio_range) { > > + ret = read_ops->read_folio_range(iter, folio, pos, plen); > > + if (ret) > > + break; > > + } else { > > + iomap_read_folio_range_async(iter, ctx, pos, plen); > > + } > > Overly long lines. > I'll fix this, sorry to make you keep having to point this out. I'll be more careful about line lengths.
