Re: [PATCH] mm: Convert DAX lock/unlock page to lock/unlock folio

[Jane Chu <jane.chu@oracle.com>]

On 8/22/2023 4:13 PM, Matthew Wilcox (Oracle) wrote:
[..]
>   
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index a6c3af985554..b81d6eb4e6ff 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1717,16 +1717,11 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags,
>   		struct dev_pagemap *pgmap)
>   {
>   	struct page *page = pfn_to_page(pfn);

Looks like the above line, that is, the 'page' pointer is no longer needed.

> +	struct folio *folio = page_folio(page);
>   	LIST_HEAD(to_kill);
>   	dax_entry_t cookie;
>   	int rc = 0;
>   
> -	/*
> -	 * Pages instantiated by device-dax (not filesystem-dax)
> -	 * may be compound pages.
> -	 */
> -	page = compound_head(page);
> -
>   	/*
>   	 * Prevent the inode from being freed while we are interrogating
>   	 * the address_space, typically this would be handled by
> @@ -1734,11 +1729,11 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags,
>   	 * also prevents changes to the mapping of this pfn until
>   	 * poison signaling is complete.
>   	 */
> -	cookie = dax_lock_page(page);
> +	cookie = dax_lock_folio(folio);
>   	if (!cookie)
>   		return -EBUSY;
>   
> -	if (hwpoison_filter(page)) {
> +	if (hwpoison_filter(&folio->page)) {
>   		rc = -EOPNOTSUPP;
>   		goto unlock;
>   	}
> @@ -1760,7 +1755,7 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags,
>   	 * Use this flag as an indication that the dax page has been
>   	 * remapped UC to prevent speculative consumption of poison.
>   	 */
> -	SetPageHWPoison(page);
> +	SetPageHWPoison(&folio->page);
>   
>   	/*
>   	 * Unlike System-RAM there is no possibility to swap in a
> @@ -1769,11 +1764,11 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags,
>   	 * SIGBUS (i.e. MF_MUST_KILL)
>   	 */
>   	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
> -	collect_procs(page, &to_kill, true);
> +	collect_procs(&folio->page, &to_kill, true);
>   
> -	unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
> +	unmap_and_kill(&to_kill, pfn, folio->mapping, folio->index, flags);
>   unlock:
> -	dax_unlock_page(page, cookie);
> +	dax_unlock_folio(folio, cookie);
>   	return rc;
>   }
>  


thanks,
-jane