RE: [PATCH v5 03/15] iommupt: Add the basic structure of the iommu implementation

From: Jason Gunthorpe jgg@nvidia.com Sent: Thursday, September 4, 2025 1:47 AM

+struct pt_iommu_collect_args {

• struct iommu_pages_list free_list;
• u8 ignore_mapped : 1;

+};

+static int __collect_tables(struct pt_range *range, void *arg,

• 	    unsigned int level, struct pt_table_p *table)
  

+{

• struct pt_state pts = pt_init(range, level, table);
• struct pt_iommu_collect_args *collect = arg;
• int ret;
• if (collect->ignore_mapped && !pt_can_have_table(&pts))

• return 0;
  

• for_each_pt_level_entry(&pts) {

• if (pts.type == PT_ENTRY_TABLE) {
  

• 	iommu_pages_list_add(&collect->free_list,
  

pts.table_lower);

• 	ret = pt_descend(&pts, arg, __collect_tables);
  

• 	if (ret)
  

• 		return ret;
  

• 	continue;
  

• }
  

• if (pts.type == PT_ENTRY_OA && !collect->ignore_mapped)
  

• 	return -EADDRINUSE;
  

• }
• return 0;

+}

I don't quite understand the purpose of ignore_mapped here. Could you mind elaborating it? the only caller always sets it now...