From: Ming Lei Date: Wed, 31 Dec 2025 03:00:56 +0000 (+0800) Subject: block: don't initialize bi_vcnt for cloned bio in bio_iov_bvec_set() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=641864314866dff382f64cd8b52fd6bf4c4d84f6;p=thirdparty%2Fkernel%2Flinux.git block: don't initialize bi_vcnt for cloned bio in bio_iov_bvec_set() 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 Reviewed-by: Nitesh Shetty Signed-off-by: Jens Axboe --- diff --git a/block/bio.c b/block/bio.c index 0e936288034e3..2359c0723b88e 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);