Re: [PATCH v3 06/26] block: Add bio_end_sector()
From: Lars Ellenberg <hidden>
Date: 2012-09-25 11:55:04
Also in:
dm-devel, lkml
On Mon, Sep 24, 2012 at 03:34:46PM -0700, Kent Overstreet wrote:
Just a little convenience macro - main reason to add it now is preparing for immutable bio vecs, it'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx into a struct bvec_iter.
For the DRBD part:
quoted hunk ↗ jump to hunk
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 01b2ac6..d90a1fd 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c@@ -1144,7 +1144,7 @@ void drbd_make_request(struct request_queue *q, struct bio *bio) /* to make some things easier, force alignment of requests within the * granularity of our hash tables */ s_enr = bio->bi_sector >> HT_SHIFT; - e_enr = bio->bi_size ? (bio->bi_sector+(bio->bi_size>>9)-1) >> HT_SHIFT : s_enr; + e_enr = (bio_end_sector(bio) - 1) >> HT_SHIFT;
You ignored the bio->bi_size ? : ; #define bio_end_sector(bio) ((bio)->bi_sector + bio_sectors(bio)) which turns out (bio->bi_sector + (bio->bi_size >> 9)) Note that bi_size may be 0, bio_end_sector(bio)-1 then is bi_sector -1, for an empty flush with bi_sector == 0, this ends up as (sector_t)-1ULL, and this code path breaks horribly. + e_enr = bio->bi_size ? (bio_end_sector(bio) - 1) >> HT_SHIFT : s_enr; Thanks, Lars