static struct dma_async_tx_descriptor *
 async_copy_data(int frombio, struct bio *bio, struct page **page,
-       sector_t sector, struct dma_async_tx_descriptor *tx,
+       unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
        struct stripe_head *sh, int no_skipcopy)
 {
        struct bio_vec bvl;
                                    !no_skipcopy)
                                        *page = bio_page;
                                else
-                                       tx = async_memcpy(*page, bio_page, page_offset,
+                                       tx = async_memcpy(*page, bio_page, page_offset + poff,
                                                  b_offset, clen, &submit);
                        } else
                                tx = async_memcpy(bio_page, *page, b_offset,
-                                                 page_offset, clen, &submit);
+                                                 page_offset + poff, clen, &submit);
                }
                /* chain the operations */
                submit.depend_tx = tx;
                        while (rbi && rbi->bi_iter.bi_sector <
                                dev->sector + RAID5_STRIPE_SECTORS(conf)) {
                                tx = async_copy_data(0, rbi, &dev->page,
+                                                    dev->offset,
                                                     dev->sector, tx, sh, 0);
                                rbi = r5_next_bio(conf, rbi, dev->sector);
                        }
                                        set_bit(R5_Discard, &dev->flags);
                                else {
                                        tx = async_copy_data(1, wbi, &dev->page,
+                                                            dev->offset,
                                                             dev->sector, tx, sh,
                                                             r5c_is_writeback(conf->log));
                                        if (dev->page != dev->orig_page &&