On Wed, 19 Nov 2014 08:52:01 +0900 Minchan Kim <minc...@kernel.org> wrote:
> > > > > > - /* > > > - * Return 0 prevents I/O fallback trial caused by rw_page fail > > > - * and upper layer can handle this IO error via page error. > > > - */ > > > + page_endio(page, rw, 0); > > > return 0; > > > > Losing the comment makes me sad. The code is somewhat odd-looking. We > > should add some words explaining why we're not reporting errors at this > > point. > > Okay. How about this? > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index decca6f161b8..1d7c90d5e0d0 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -975,6 +975,12 @@ static int zram_rw_page(struct block_device *bdev, > sector_t sector, > err = zram_bvec_rw(zram, &bv, index, offset, rw); > out_unlock: > up_read(&zram->init_lock); > + /* > + * If I/O fails, just return error without calling page_endio. > + * It causes resubmit the I/O with bio request by rw_page fallback > + * and bio I/O complete handler does things to handle the error > + * (e.g., set_page_dirty of swap_writepage fail). > + */ > if (err == 0) > page_endio(page, rw, 0); > return err; I don't understand the comment :( bdev_read_page() doesn't resubmit the IO if block_device_operations.rw_page() returns zero and it's unclear how the bio I/O complete handler (which one?) gets involved. It would help in the comment was more specific. Instead of using vague terms like "rw_page fallback" and "bio I/O complete handler", use actual function names so the reader understand exactly what code we're referring to. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
