[PATCH v9 04/25] mm: Move readahead nr_pages check into read_pages

Matthew Wilcox
2020-03-20T14:24:40Z

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>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
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);
}

/*
--
2.25.1