+/*
+ * Select the next per-ag structure to iterate during the walk. The reclaim
+ * walk is optimised only to walk AGs with reclaimable inodes in them.
+ */
+static struct xfs_perag *
+xfs_inode_ag_iter_next_pag(
+ struct xfs_mount *mp,
+ xfs_agnumber_t *first,
+ int tag)
+{
+ struct xfs_perag *pag = NULL;
+
+ if (tag == XFS_ICI_RECLAIM_TAG) {
+ int found;
+ int ref;
+
+ spin_lock(&mp->m_perag_lock);
+ found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
+ (void **)&pag, *first, 1, tag);
+ if (found <= 0) {
+ spin_unlock(&mp->m_perag_lock);
+ return NULL;
+ }
+ *first = pag->pag_agno + 1;
+ /* open coded pag reference increment */
+ ref = atomic_inc_return(&pag->pag_ref);
+ spin_unlock(&mp->m_perag_lock);
+ trace_xfs_perag_get_reclaim(mp, pag->pag_agno, ref, _RET_IP_);
+ } else {
+ pag = xfs_perag_get(mp, *first);
+ (*first)++;
+ }
+ return pag;
+}
+