RB_PREV
while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) {
#define rb_prev(node) RB_PREV(linux_root, NULL, (node))
prev = RB_PREV(iommu_gas_entries_tree, &domain->rb_root, next);
ip = RB_PREV(iommu_gas_entries_tree, &domain->rb_root, entry);
prev = RB_PREV(iommu_gas_entries_tree, &domain->rb_root, next);
offset_prv = RB_PREV(file_offset_head, &priv_user->file_offset, offset);
if (((cmpelm = RB_PREV(name, head, elm)) != NULL && \