Re: [PATCH] mm/huge_memory: fix dereferencing invalid pmd migration entry

[Hugh Dickins]

On Wed, 16 Apr 2025, David Hildenbrand wrote:
> 
> Why not something like
> 
> struct folio *entry_folio;
> 
> if (folio) {	
> 	if (is_pmd_migration_entry(*pmd))
> 		entry_folio = pfn_swap_entry_folio(pmd_to_swp_entry(*pmd)));
> 	else
> 		entry_folio = pmd_folio(*pmd));
> 
> 	if (folio != entry_folio)
> 		return;
> }

My own preference is to not add unnecessary code: 
if folio and pmd_migration entry, we're not interested in entry_folio.
But yes it could be written in lots of other ways.

Hugh