Re: [PATCH 1/1] mm: Convert pagecache_isize_extended to use a folio

["Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>]

On Wed, Feb 28, 2024 at 06:22:28PM +0000, Matthew Wilcox (Oracle) wrote:
> Remove four hidden calls to compound_head().  Also exit early if the
> filesystem block size is >= PAGE_SIZE instead of just equal to PAGE_SIZE.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Look good to me.
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>

> ---
>  mm/truncate.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/mm/truncate.c b/mm/truncate.c
> index 725b150e47ac..25776e1915b8 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -781,31 +781,29 @@ void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
>  {
>  	int bsize = i_blocksize(inode);
>  	loff_t rounded_from;
> -	struct page *page;
> -	pgoff_t index;
> +	struct folio *folio;
>  
>  	WARN_ON(to > inode->i_size);
>  
> -	if (from >= to || bsize == PAGE_SIZE)
> +	if (from >= to || bsize >= PAGE_SIZE)
>  		return;
>  	/* Page straddling @from will not have any hole block created? */
>  	rounded_from = round_up(from, bsize);
>  	if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
>  		return;
>  
> -	index = from >> PAGE_SHIFT;
> -	page = find_lock_page(inode->i_mapping, index);
> -	/* Page not cached? Nothing to do */
> -	if (!page)
> +	folio = filemap_lock_folio(inode->i_mapping, from / PAGE_SIZE);
> +	/* Folio not cached? Nothing to do */
> +	if (IS_ERR(folio))
>  		return;
>  	/*
> -	 * See clear_page_dirty_for_io() for details why set_page_dirty()
> +	 * See folio_clear_dirty_for_io() for details why folio_mark_dirty()
>  	 * is needed.
>  	 */
> -	if (page_mkclean(page))
> -		set_page_dirty(page);
> -	unlock_page(page);
> -	put_page(page);
> +	if (folio_mkclean(folio))
> +		folio_mark_dirty(folio);
> +	folio_unlock(folio);
> +	folio_put(folio);
>  }
>  EXPORT_SYMBOL(pagecache_isize_extended);
>  
> -- 
> 2.43.0
>