diff mbox series

[v7,04/24] mm: Move readahead nr_pages check into read_pages

Message ID 20200219210103.32400-5-willy@infradead.org
State New
Headers show
Series Change readahead API | expand

Commit Message

Matthew Wilcox Feb. 19, 2020, 9 p.m. UTC
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Simplify the callers by moving the check for nr_pages and the BUG_ON
into read_pages().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/readahead.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

Comments

Zi Yan Feb. 20, 2020, 2:36 p.m. UTC | #1
On 19 Feb 2020, at 16:00, Matthew Wilcox wrote:

> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> Simplify the callers by moving the check for nr_pages and the BUG_ON
> into read_pages().
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/readahead.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/mm/readahead.c b/mm/readahead.c
> index 61b15b6b9e72..9fcd4e32b62d 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -119,6 +119,9 @@ static void read_pages(struct address_space *mapping, struct file *filp,
>  	struct blk_plug plug;
>  	unsigned page_idx;
>
> +	if (!nr_pages)
> +		return;
> +
>  	blk_start_plug(&plug);
>
>  	if (mapping->a_ops->readpages) {
> @@ -138,6 +141,8 @@ static void read_pages(struct address_space *mapping, struct file *filp,
>
>  out:
>  	blk_finish_plug(&plug);
> +
> +	BUG_ON(!list_empty(pages));
>  }
>
>  /*
> @@ -180,8 +185,7 @@ void __do_page_cache_readahead(struct address_space *mapping,
>  			 * contiguous pages before continuing with the next
>  			 * batch.
>  			 */
> -			if (nr_pages)
> -				read_pages(mapping, filp, &page_pool, nr_pages,
> +			read_pages(mapping, filp, &page_pool, nr_pages,
>  						gfp_mask);
>  			nr_pages = 0;
>  			continue;
> @@ -202,9 +206,7 @@ void __do_page_cache_readahead(struct address_space *mapping,
>  	 * uptodate then the caller will launch readpage again, and
>  	 * will then handle the error.
>  	 */
> -	if (nr_pages)
> -		read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
> -	BUG_ON(!list_empty(&page_pool));
> +	read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
>  }
>
>  /*
> -- 
> 2.25.0

Looks good to me. Thanks.

Reviewed-by: Zi Yan <ziy@nvidia.com>


--
Best Regards,
Yan Zi
John Hubbard Feb. 21, 2020, 4:24 a.m. UTC | #2
On 2/19/20 1:00 PM, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Simplify the callers by moving the check for nr_pages and the BUG_ON
> into read_pages().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/readahead.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 

Looks nice,

    Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
Christoph Hellwig Feb. 24, 2020, 9:34 p.m. UTC | #3
On Wed, Feb 19, 2020 at 01:00:43PM -0800, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Simplify the callers by moving the check for nr_pages and the BUG_ON
> into read_pages().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/mm/readahead.c b/mm/readahead.c
index 61b15b6b9e72..9fcd4e32b62d 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -119,6 +119,9 @@  static void read_pages(struct address_space *mapping, struct file *filp,
 	struct blk_plug plug;
 	unsigned page_idx;
 
+	if (!nr_pages)
+		return;
+
 	blk_start_plug(&plug);
 
 	if (mapping->a_ops->readpages) {
@@ -138,6 +141,8 @@  static void read_pages(struct address_space *mapping, struct file *filp,
 
 out:
 	blk_finish_plug(&plug);
+
+	BUG_ON(!list_empty(pages));
 }
 
 /*
@@ -180,8 +185,7 @@  void __do_page_cache_readahead(struct address_space *mapping,
 			 * contiguous pages before continuing with the next
 			 * batch.
 			 */
-			if (nr_pages)
-				read_pages(mapping, filp, &page_pool, nr_pages,
+			read_pages(mapping, filp, &page_pool, nr_pages,
 						gfp_mask);
 			nr_pages = 0;
 			continue;
@@ -202,9 +206,7 @@  void __do_page_cache_readahead(struct address_space *mapping,
 	 * uptodate then the caller will launch readpage again, and
 	 * will then handle the error.
 	 */
-	if (nr_pages)
-		read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
-	BUG_ON(!list_empty(&page_pool));
+	read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
 }
 
 /*