- if (unlikely(bio->bi_rw & REQ_FLUSH)) {
- md_flush_request(mddev, bio);
- return;
- }
-
- /* If this request crosses a chunk boundary, we need to
- * split it. This will only happen for 1 PAGE (or less) requests.
- */
- if (unlikely((bio->bi_sector & chunk_mask) + bio_sectors(bio)
- > chunk_sects
- && (conf->geo.near_copies < conf->geo.raid_disks
- || conf->prev.near_copies < conf->prev.raid_disks))) {
- struct bio_pair *bp;
- /* Sanity check -- queue functions should prevent this happening */
- if (bio_segments(bio) > 1)
- goto bad_map;
- /* This is a one page bio that upper layers
- * refuse to split for us, so we need to split it.
- */
- bp = bio_split(bio,
- chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
-
- /* Each of these 'make_request' calls will call 'wait_barrier'.
- * If the first succeeds but the second blocks due to the resync
- * thread raising the barrier, we will deadlock because the
- * IO to the underlying device will be queued in generic_make_request
- * and will never complete, so will never reduce nr_pending.
- * So increment nr_waiting here so no new raise_barriers will
- * succeed, and so the second wait_barrier cannot block.
- */
- spin_lock_irq(&conf->resync_lock);
- conf->nr_waiting++;
- spin_unlock_irq(&conf->resync_lock);
-
- make_request(mddev, &bp->bio1);
- make_request(mddev, &bp->bio2);
-
- spin_lock_irq(&conf->resync_lock);
- conf->nr_waiting--;
- wake_up(&conf->wait_barrier);
- spin_unlock_irq(&conf->resync_lock);
-
- bio_pair_release(bp);
- return;
- bad_map:
- printk("md/raid10:%s: make_request bug: can't convert block across chunks"
- " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
- (unsigned long long)bio->bi_sector, bio_sectors(bio) / 2);
-
- bio_io_error(bio);
- return;
- }
-
- md_write_start(mddev, bio);
-
- /*
- * Register the new request and wait if the reconstruction
- * thread has put up a bar for new requests.
- * Continue immediately if no resync is active currently.
- */
- wait_barrier(conf);
-