btrfs: raid56: reduce indentation in lock_stripe_add

In lock_stripe_add() we're traversing the stripe hash list and check if
the current list element's raid_map equals is equal to the raid bio's
raid_map. If both are equal we continue processing.

If we'd check for inequality instead of equality we can reduce one level
of indentation.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -682,62 +682,59 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
 
 	spin_lock_irqsave(&h->lock, flags);
 	list_for_each_entry(cur, &h->hash_list, hash_list) {
-		if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
-			spin_lock(&cur->bio_list_lock);
-
-			/* can we steal this cached rbio's pages? */
-			if (bio_list_empty(&cur->bio_list) &&
-			    list_empty(&cur->plug_list) &&
-			    test_bit(RBIO_CACHE_BIT, &cur->flags) &&
-			    !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
-				list_del_init(&cur->hash_list);
-				refcount_dec(&cur->refs);
-
-				steal_rbio(cur, rbio);
-				cache_drop = cur;
-				spin_unlock(&cur->bio_list_lock);
+		if (cur->bbio->raid_map[0] != rbio->bbio->raid_map[0])
+			continue;
 
-				goto lockit;
-			}
+		spin_lock(&cur->bio_list_lock);
 
-			/* can we merge into the lock owner? */
-			if (rbio_can_merge(cur, rbio)) {
-				merge_rbio(cur, rbio);
-				spin_unlock(&cur->bio_list_lock);
-				freeit = rbio;
-				ret = 1;
-				goto out;
-			}
+		/* Can we steal this cached rbio's pages? */
+		if (bio_list_empty(&cur->bio_list) &&
+		    list_empty(&cur->plug_list) &&
+		    test_bit(RBIO_CACHE_BIT, &cur->flags) &&
+		    !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
+			list_del_init(&cur->hash_list);
+			refcount_dec(&cur->refs);
 
+			steal_rbio(cur, rbio);
+			cache_drop = cur;
+			spin_unlock(&cur->bio_list_lock);
 
-			/*
-			 * we couldn't merge with the running
-			 * rbio, see if we can merge with the
-			 * pending ones.  We don't have to
-			 * check for rmw_locked because there
-			 * is no way they are inside finish_rmw
-			 * right now
-			 */
-			list_for_each_entry(pending, &cur->plug_list,
-					    plug_list) {
-				if (rbio_can_merge(pending, rbio)) {
-					merge_rbio(pending, rbio);
-					spin_unlock(&cur->bio_list_lock);
-					freeit = rbio;
-					ret = 1;
-					goto out;
-				}
-			}
+			goto lockit;
+		}
 
-			/* no merging, put us on the tail of the plug list,
-			 * our rbio will be started with the currently
-			 * running rbio unlocks
-			 */
-			list_add_tail(&rbio->plug_list, &cur->plug_list);
+		/* Can we merge into the lock owner? */
+		if (rbio_can_merge(cur, rbio)) {
+			merge_rbio(cur, rbio);
 			spin_unlock(&cur->bio_list_lock);
+			freeit = rbio;
 			ret = 1;
 			goto out;
 		}
+
+
+		/*
+		 * We couldn't merge with the running rbio, see if we can merge
+		 * with the pending ones.  We don't have to check for rmw_locked
+		 * because there is no way they are inside finish_rmw right now
+		 */
+		list_for_each_entry(pending, &cur->plug_list, plug_list) {
+			if (rbio_can_merge(pending, rbio)) {
+				merge_rbio(pending, rbio);
+				spin_unlock(&cur->bio_list_lock);
+				freeit = rbio;
+				ret = 1;
+				goto out;
+			}
+		}
+
+		/*
+		 * No merging, put us on the tail of the plug list, our rbio
+		 * will be started with the currently running rbio unlocks
+		 */
+		list_add_tail(&rbio->plug_list, &cur->plug_list);
+		spin_unlock(&cur->bio_list_lock);
+		ret = 1;
+		goto out;
 	}
 lockit:
 	refcount_inc(&rbio->refs);