Re: [PATCH RFC] block: Eliminate first argument of submit_bio()

Jens Axboe
2014-06-02T16:04:41Z

On 2014-06-02 03:44, Bart Van Assche wrote:
> The submit_bio() API is confusing. Merge functions like
> raid5_mergeable_bvec() can only work correctly if bi_rw is set
> before bio_add_page() has been called. submit_bio() modifies
> bi_rw after bio_add_page() has been called. Hence remove the
> first argument of submit_bio() and let the caller set bi_rw.
> Note: some but not all submit_bio() callers have been fixed
> such that bi_rw is set before bio_add_page() is called.
>
> See also http://thread.gmane.org/gmane.comp.file-systems.ocfs2.devel/7988
> for a prior discussion of this topic.
>
> Compile tested only, hence the "RFC".

It's a good cleanup, makes the API harder to misuse. The fact that rw
needs to be set before add_page() was a later addition, and we've
suffered from that.

Will need some testing, but after that should be good for 3.17.

--
Jens Axboe