+retry_discard:
+ r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+ r10_bio->mddev = mddev;
+ r10_bio->state = 0;
+ r10_bio->sectors = 0;
+ memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
+ wait_blocked_dev(mddev, r10_bio);
+
+ /*
+ * For far layout it needs more than one r10bio to cover all regions.
+ * Inspired by raid10_sync_request, we can use the first r10bio->master_bio
+ * to record the discard bio. Other r10bio->master_bio record the first
+ * r10bio. The first r10bio only release after all other r10bios finish.
+ * The discard bio returns only first r10bio finishes
+ */
+ if (first_copy) {
+ r10_bio->master_bio = bio;
+ set_bit(R10BIO_Discard, &r10_bio->state);
+ first_copy = false;
+ first_r10bio = r10_bio;
+ } else
+ r10_bio->master_bio = (struct bio *)first_r10bio;
+