Re: [PATCH v1 23/54] bcache: handle bio_clone() & bvec updating for multipage bvecs
From: Coly Li
Date: Fri Dec 30 2016 - 06:01:49 EST
On 2016/12/27 äå11:56, Ming Lei wrote:
> The incoming bio may be too big to be cloned into
> one singlepage bvecs bio, so split the bio and
> check the splitted bio one by one.
>
> Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
> ---
> drivers/md/bcache/debug.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
> index 48d03e8b3385..18b2d2d138e3 100644
> --- a/drivers/md/bcache/debug.c
> +++ b/drivers/md/bcache/debug.c
> @@ -103,7 +103,7 @@ void bch_btree_verify(struct btree *b)
> up(&b->io_mutex);
> }
>
> -void bch_data_verify(struct cached_dev *dc, struct bio *bio)
> +static void __bch_data_verify(struct cached_dev *dc, struct bio *bio)
> {
> char name[BDEVNAME_SIZE];
> struct bio *check;
> @@ -116,7 +116,7 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)
> * in the new cloned bio because each single page need
> * to assign to each bvec of the new bio.
> */
> - check = bio_clone(bio, GFP_NOIO);
> + check = bio_clone_sp(bio, GFP_NOIO);
> if (!check)
> return;
> check->bi_opf = REQ_OP_READ;
> @@ -151,6 +151,26 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)
> bio_put(check);
> }
>
> +void bch_data_verify(struct cached_dev *dc, struct bio *bio)
> +{
> + struct request_queue *q = bdev_get_queue(bio->bi_bdev);
> + struct bio *clone = bio_clone_fast(bio, GFP_NOIO, q->bio_split);
> + unsigned sectors;
> +
> + while (!bio_can_convert_to_sp(clone, §ors)) {
> + struct bio *split = bio_split(clone, sectors,
> + GFP_NOIO, q->bio_split);
> +
> + __bch_data_verify(dc, split);
> + bio_put(split);
> + }
> +
> + if (bio_sectors(clone))
> + __bch_data_verify(dc, clone);
> +
> + bio_put(clone);
> +}
> +
Hi Lei,
The above patch is good IMHO. Just wondering why not use the classical
style ? something like,
do {
if (!bio_can_convert_to_sp(clone, §ors))
split = bio_split(clone, sectors,
GFP_NOIO, q->bio_split);
else
split = clone;
__bch_data_verity(gc, split);
bio_put(split);
} while (split != clone);
I guess maybe the above style generates less binary code.
--
Coly Li