xfs: replace open-coded bitmap weight logic

Add a xbitmap_hweight helper function so that we can get rid of the
open-coded loop.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/scrub/agheader_repair.c

@@ -482,8 +482,6 @@ xrep_agfl_collect_blocks(
 	struct xrep_agfl	ra;
 	struct xfs_mount	*mp = sc->mp;
 	struct xfs_btree_cur	*cur;
-	struct xbitmap_range	*br;
-	struct xbitmap_range	*n;
 	int			error;
 
 	ra.sc = sc;
@@ -527,14 +525,8 @@ xrep_agfl_collect_blocks(
 	 * Calculate the new AGFL size.  If we found more blocks than fit in
 	 * the AGFL we'll free them later.
 	 */
-	*flcount = 0;
-	for_each_xbitmap_extent(br, n, agfl_extents) {
-		*flcount += br->len;
-		if (*flcount > xfs_agfl_size(mp))
-			break;
-	}
-	if (*flcount > xfs_agfl_size(mp))
-		*flcount = xfs_agfl_size(mp);
+	*flcount = min_t(uint64_t, xbitmap_hweight(agfl_extents),
+			 xfs_agfl_size(mp));
 	return 0;
 
 err:

fs/xfs/scrub/bitmap.c

@@ -297,3 +297,18 @@ xbitmap_set_btblocks(
 	return xfs_btree_visit_blocks(cur, xbitmap_collect_btblock,
 			XFS_BTREE_VISIT_ALL, bitmap);
 }
+
+/* How many bits are set in this bitmap? */
+uint64_t
+xbitmap_hweight(
+	struct xbitmap		*bitmap)
+{
+	struct xbitmap_range	*bmr;
+	struct xbitmap_range	*n;
+	uint64_t		ret = 0;
+
+	for_each_xbitmap_extent(bmr, n, bitmap)
+		ret += bmr->len;
+
+	return ret;
+}

fs/xfs/scrub/bitmap.h

@@ -32,5 +32,6 @@ int xbitmap_set_btcur_path(struct xbitmap *bitmap,
 		struct xfs_btree_cur *cur);
 int xbitmap_set_btblocks(struct xbitmap *bitmap,
 		struct xfs_btree_cur *cur);
+uint64_t xbitmap_hweight(struct xbitmap *bitmap);
 
 #endif	/* __XFS_SCRUB_BITMAP_H__ */