Re: [PATCH v3 04/49] mm: page_io.c: comment on direct access to bvec table

[Christoph Hellwig]

Can we just add a bio_first_page macro that always return the first
page in the bio?

[PATCH v3 04/49] mm: page_io.c: comment on direct access to bvec table

[Ming Lei]

Cc: Andrew Morton 
Cc: linux...@kvack.org
Signed-off-by: Ming Lei 
---
 mm/page_io.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/page_io.c b/mm/page_io.c
index b6c4ac388209..11c6f4a9a25b 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -43,6 +43,7 @@ static struct bio *get_swap_bio(gfp_t gfp_flags,
 
 void end_swap_bio_write(struct bio *bio)
 {
+   /* single page bio, safe for multipage bvec */
struct page *page = bio->bi_io_vec[0].bv_page;
 
if (bio->bi_status) {
@@ -116,6 +117,7 @@ static void swap_slot_free_notify(struct page *page)
 
 static void end_swap_bio_read(struct bio *bio)
 {
+   /* single page bio, safe for multipage bvec */
struct page *page = bio->bi_io_vec[0].bv_page;
struct task_struct *waiter = bio->bi_private;
 
-- 
2.9.4