All direct access to bvec table are safe even after multipage bvec is supported.
Cc: [email protected] Acked-by: Coly Li <[email protected]> Signed-off-by: Ming Lei <[email protected]> --- drivers/md/bcache/btree.c | 1 + drivers/md/bcache/util.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 11c5503d31dc..c09f3dd4bf07 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -432,6 +432,7 @@ static void do_btree_node_write(struct btree *b) continue_at(cl, btree_node_write_done, NULL); } else { + /* No problem for multipage bvec since the bio is just allocated */ b->bio->bi_vcnt = 0; bch_bio_map(b->bio, i); diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c index e548b8b51322..61813d230015 100644 --- a/drivers/md/bcache/util.c +++ b/drivers/md/bcache/util.c @@ -249,6 +249,13 @@ uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done) : 0; } +/* + * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly, + * the preferred way is bio_add_page, but in this case, bch_bio_map() + * supposes that the bvec table is empty, so it is safe to access + * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is + * supported. + */ void bch_bio_map(struct bio *bio, void *base) { size_t size = bio->bi_iter.bi_size; -- 2.9.5
