On Wed, Jun 27, 2018 at 01:12:31PM -0700, Bart Van Assche wrote: > Although __bio_clone_fast() copies bi_io_vec, it does not copy bi_vcnt, > the number of elements in bi_io_vec[] that contains data. Copy bi_vcnt > such that code that needs this member behaves identically for original > and for cloned requests. > > Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Mike Snitzer <snitzer@xxxxxxxxxx> > Cc: Ming Lei <ming.lei@xxxxxxxxxx> > Cc: Hannes Reinecke <hare@xxxxxxxx> > Cc: Johannes Thumshirn <jthumshirn@xxxxxxx> > --- > block/bio.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/block/bio.c b/block/bio.c > index f7e3d88bd0b6..55f8e0dedd69 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -605,6 +605,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src) > bio->bi_opf = bio_src->bi_opf; > bio->bi_write_hint = bio_src->bi_write_hint; > bio->bi_iter = bio_src->bi_iter; > + bio->bi_vcnt = bio_src->bi_vcnt; > bio->bi_io_vec = bio_src->bi_io_vec; No, don't do that. For a cloned bio, both .bi_vcnt and .bi_io_vec can't be used directly, and we have done huge such cleanup for supporting multipage bvec, that is the great idea of immutable bvecs invented by Kent. Thanks, Ming
