Re: [PATCH 01/10] splice: Use a folio in page_cache_pipe_buf_try_steal()

[Miaohe Lin <linmiaohe@huawei.com>]

On 2022/2/15 4:00, Matthew Wilcox (Oracle) wrote:
> This saves a lot of calls to compound_head().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  fs/splice.c | 21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> 

LGTM. Thanks.

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

> diff --git a/fs/splice.c b/fs/splice.c
> index 5dbce4dcc1a7..23ff9c303abc 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -47,26 +47,27 @@ static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe,
>  		struct pipe_buffer *buf)
>  {
>  	struct page *page = buf->page;
> +	struct folio *folio = page_folio(page);
>  	struct address_space *mapping;
>  
> -	lock_page(page);
> +	folio_lock(folio);
>  
> -	mapping = page_mapping(page);
> +	mapping = folio_mapping(folio);
>  	if (mapping) {
> -		WARN_ON(!PageUptodate(page));
> +		WARN_ON(!folio_test_uptodate(folio));
>  
>  		/*
>  		 * At least for ext2 with nobh option, we need to wait on
> -		 * writeback completing on this page, since we'll remove it
> +		 * writeback completing on this folio, since we'll remove it
>  		 * from the pagecache.  Otherwise truncate wont wait on the
> -		 * page, allowing the disk blocks to be reused by someone else
> +		 * folio, allowing the disk blocks to be reused by someone else
>  		 * before we actually wrote our data to them. fs corruption
>  		 * ensues.
>  		 */
> -		wait_on_page_writeback(page);
> +		folio_wait_writeback(folio);
>  
> -		if (page_has_private(page) &&
> -		    !try_to_release_page(page, GFP_KERNEL))
> +		if (folio_has_private(folio) &&
> +		    !filemap_release_folio(folio, GFP_KERNEL))
>  			goto out_unlock;
>  
>  		/*
> @@ -80,11 +81,11 @@ static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe,
>  	}
>  
>  	/*
> -	 * Raced with truncate or failed to remove page from current
> +	 * Raced with truncate or failed to remove folio from current
>  	 * address space, unlock and return failure.
>  	 */
>  out_unlock:
> -	unlock_page(page);
> +	folio_unlock(folio);
>  	return false;
>  }
>  
>