xfs: add a xfs_groups_to_rfsbs helper

Plus a rtgroup wrapper and use that to avoid overflows when converting
zone/rtg counts to block counts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_group.h

@@ -98,6 +98,15 @@ xfs_group_max_blocks(
 	return xg->xg_mount->m_groups[xg->xg_type].blocks;
 }
 
+static inline xfs_rfsblock_t
+xfs_groups_to_rfsbs(
+	struct xfs_mount	*mp,
+	uint32_t		nr_groups,
+	enum xfs_group_type	type)
+{
+	return (xfs_rfsblock_t)mp->m_groups[type].blocks * nr_groups;
+}
+
 static inline xfs_fsblock_t
 xfs_group_start_fsb(
 	struct xfs_group	*xg)

fs/xfs/libxfs/xfs_rtgroup.h

@@ -371,4 +371,12 @@ static inline int xfs_initialize_rtgroups(struct xfs_mount *mp,
 # define xfs_rtgroup_get_geometry(rtg, rgeo)	(-EOPNOTSUPP)
 #endif /* CONFIG_XFS_RT */
 
+static inline xfs_rfsblock_t
+xfs_rtgs_to_rfsbs(
+	struct xfs_mount	*mp,
+	uint32_t		nr_groups)
+{
+	return xfs_groups_to_rfsbs(mp, nr_groups, XG_TYPE_RTG);
+}
+
 #endif /* __LIBXFS_RTGROUP_H */

fs/xfs/xfs_zone_gc.c

@@ -181,8 +181,7 @@ xfs_zoned_need_gc(
 	available = xfs_estimate_freecounter(mp, XC_FREE_RTAVAILABLE);
 
 	if (available <
-	    mp->m_groups[XG_TYPE_RTG].blocks *
-	    (mp->m_max_open_zones - XFS_OPEN_GC_ZONES))
+	    xfs_rtgs_to_rfsbs(mp, mp->m_max_open_zones - XFS_OPEN_GC_ZONES))
 		return true;
 
 	free = xfs_estimate_freecounter(mp, XC_FREE_RTEXTENTS);

fs/xfs/xfs_zone_space_resv.c

@@ -54,12 +54,10 @@ xfs_zoned_default_resblks(
 {
 	switch (ctr) {
 	case XC_FREE_RTEXTENTS:
-		return (uint64_t)XFS_RESERVED_ZONES *
-			mp->m_groups[XG_TYPE_RTG].blocks +
-			mp->m_sb.sb_rtreserved;
+		return xfs_rtgs_to_rfsbs(mp, XFS_RESERVED_ZONES) +
+				mp->m_sb.sb_rtreserved;
 	case XC_FREE_RTAVAILABLE:
-		return (uint64_t)XFS_GC_ZONES *
-			mp->m_groups[XG_TYPE_RTG].blocks;
+		return xfs_rtgs_to_rfsbs(mp, XFS_GC_ZONES);
 	default:
 		ASSERT(0);
 		return 0;