On Fri, Jun 29, 2018 at 01:00:33PM -0700, Bart Van Assche wrote: > On 06/28/18 17:04, Kent Overstreet wrote: > > On Thu, Jun 28, 2018 at 04:54:44PM -0700, Bart Van Assche wrote: > > > Thanks for chiming in. The linux-block mailing list is archived by > > > multiple > > > websites. The entire e-mail thread is available on e.g. > > > https://www.mail-archive.com/linux-block@vger.kernel.org/msg23006.html. > > > > > > I have a question for you: at least in kernel v4.17 bio_clone_bioset() > > > copies bi_vcnt from the source to the destination bio. However, > > > __bio_clone_fast() doesn't copy bi_vcnt. Isn't that an inconsistency? > > > > No - when you use bio_clone_bioset() you get a bio that you own and can do > > whatever you want with, so it does make sense for it to initialize bi_vcnt. > > > > e.g. you could use bio_clone_bioset() when you're going to be bouncing a > > bio, > > iterating over each bvec and allocating a new page and copying data from > > the old > > page to the new page. > > Hello Kent, > > Have you considered to explain this in a comment above __bio_clone_fast() to > avoid that the next person who reads that function gets confused?
Well, there is a large comment in bio_clone_bioset() that you must have found...
