Re: [PATCH v2 1/5] mm,hugetlb: Change mechanism to detect a COW on private mapping

[David Hildenbrand]

>   
> -	/*
> -	 * hugetlb_wp() requires page locks of pte_page(vmf.orig_pte) and
> -	 * pagecache_folio, so here we need take the former one
> -	 * when folio != pagecache_folio or !pagecache_folio.
> -	 */
> +	/* hugetlb_wp() requires page locks of pte_page(vmf.orig_pte) */
>   	folio = page_folio(pte_page(vmf.orig_pte));
> -	if (folio != pagecache_folio)
> -		if (!folio_trylock(folio)) {
> -			need_wait_lock = 1;
> -			goto out_ptl;
> -		}
> -
> +	folio_lock(folio);
>   	folio_get(folio);

Just realized that this won't work for this patch here, as we are 
holding the PTL.

In patch #2 you do the right thing.

--
Cheers,

David / dhildenb