Re: [PATCH] mm/filemap: introduce local helper for_each_folio

[Matthew Wilcox <willy@infradead.org>]

On Mon, Sep 09, 2024 at 02:17:35PM +0800, chensong_2000@189.cn wrote:
> From: Song Chen <chensong_2000@189.cn>
> 
> Introduce for_each_folio to iterate folios in xarray for code style
> compliance and better readability.

I'm not sure this is really worth it.

> Signed-off-by: Song Chen <chensong_2000@189.cn>
> ---
>  mm/filemap.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index d62150418b91..5386348acacd 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -62,6 +62,9 @@
>  
>  #include "swap.h"
>  
> +#define for_each_folio(folio, xas, max)	\
> +	for (folio = xas_load(&xas);	\
> +		 folio && xas.xa_index <= max; folio = xas_next(&xas))
>  /*
>   * Shared mappings implemented 30.11.1994. It's not fully working yet,
>   * though.
> @@ -2170,8 +2173,7 @@ unsigned filemap_get_folios_contig(struct address_space *mapping,
>  
>  	rcu_read_lock();
>  
> -	for (folio = xas_load(&xas); folio && xas.xa_index <= end;
> -			folio = xas_next(&xas)) {
> +	for_each_folio(folio, xas, end) {
>  		if (xas_retry(&xas, folio))
>  			continue;
>  		/*
> @@ -2306,7 +2308,7 @@ static void filemap_get_read_batch(struct address_space *mapping,
>  	struct folio *folio;
>  
>  	rcu_read_lock();
> -	for (folio = xas_load(&xas); folio; folio = xas_next(&xas)) {
> +	for_each_folio(folio, xas, ULONG_MAX) {
>  		if (xas_retry(&xas, folio))
>  			continue;
>  		if (xas.xa_index > max || xa_is_value(folio))
> -- 
> 2.34.1
> 
>