block: Add bio_list_peek()

Introduce bio_list_peek(), to obtain a pointer to the first bio on the bio_list
without actually removing it from the list. This is needed when you want to
serialize based on the list being empty or not.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Geert Uytterhoeven 2009-06-10 04:38:40 +00:00 committed by Benjamin Herrenschmidt
parent c2e95c6d7a
commit 13685a1654

View file

@ -590,6 +590,11 @@ static inline void bio_list_merge_head(struct bio_list *bl,
bl->head = bl2->head;
}
static inline struct bio *bio_list_peek(struct bio_list *bl)
{
return bl->head;
}
static inline struct bio *bio_list_pop(struct bio_list *bl)
{
struct bio *bio = bl->head;