On Fri, 14 Dec 2007 17:26:28 +1100 NeilBrown [off-list ref] wrote:

+		mddev_unlock(rdev->mddev);
+		ITERATE_MDDEV(mddev, tmp) {
+			mdk_rdev_t *rdev2;
+
+			mddev_lock(mddev);
+			ITERATE_RDEV(mddev, rdev2, tmp2)
+				if (test_bit(AllReserved, &rdev2->flags) ||
+				    (rdev->bdev == rdev2->bdev &&
+				     rdev != rdev2 &&
+				     overlaps(rdev->data_offset, rdev->size,
+					    rdev2->data_offset, rdev2->size))) {
+					overlap = 1;
+					break;
+				}
+			mddev_unlock(mddev);
+			if (overlap) {
+				mddev_put(mddev);
+				break;
+			}
+		}

eww, ITERATE_MDDEV() and ITERATE_RDEV() are an eyesore.

for_each_mddev() and for_each_rdev() would at least mean the reader doesn't
need to check the implementation when wondering what that `break' is
breaking from.

 #define	In_sync		2		/* device is in_sync with rest of array */
 #define	WriteMostly	4		/* Avoid reading if at all possible */
 #define	BarriersNotsupp	5		/* BIO_RW_BARRIER is not supported */
+#define	AllReserved	6		/* If whole device is reserved for

The naming style here is inconsistent.

A task for the keen would be to convert these to an enum and add some
namespacing prefix to them.