rbd: make snap_size order parameter optional

Only one of the two callers of _rbd_dev_v2_snap_size() needs the
order value returned.  So make that an optional argument--a null
pointer if the caller doesn't need it.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 28b652c..1e01f0d 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3494,7 +3494,8 @@ static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
        if (ret < sizeof (size_buf))
                return -ERANGE;
 
-       *order = size_buf.order;
+       if (order)
+               *order = size_buf.order;
        *snap_size = le64_to_cpu(size_buf.size);
 
        dout("  snap_id 0x%016llx order = %u, snap_size = %llu\n",
@@ -3939,11 +3940,10 @@ static char *rbd_dev_v2_snap_info(struct rbd_device *rbd_dev, u32 which,
                u64 *snap_size, u64 *snap_features)
 {
        u64 snap_id;
-       u8 order;
        int ret;
 
        snap_id = rbd_dev->header.snapc->snaps[which];
-       ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, &order, snap_size);
+       ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, snap_size);
        if (ret)
                return ERR_PTR(ret);
        ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, snap_features);