bio_iov_bvec_set() creates a cloned bio that borrows a bvec array from an iov_iter. For cloned bios, bi_vcnt is meaningless because iteration is controlled entirely by bi_iter (bi_idx, bi_size, bi_bvec_done), not by bi_vcnt. Remove the incorrect bi_vcnt assignment. Explicitly initialize bi_iter.bi_idx to 0 to ensure iteration starts at the first bvec. While bi_idx is typically already zero from bio initialization, making this explicit improves clarity and correctness. This change also avoids accessing iter->nr_segs, which is an iov_iter implementation detail that block code should not depend on. Signed-off-by: Ming Lei --- block/bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/bio.c b/block/bio.c index 0e936288034e..2359c0723b88 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1165,8 +1165,8 @@ void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter) { WARN_ON_ONCE(bio->bi_max_vecs); - bio->bi_vcnt = iter->nr_segs; bio->bi_io_vec = (struct bio_vec *)iter->bvec; + bio->bi_iter.bi_idx = 0; bio->bi_iter.bi_bvec_done = iter->iov_offset; bio->bi_iter.bi_size = iov_iter_count(iter); bio_set_flag(bio, BIO_CLONED); -- 2.47.0