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

From: Jens Axboe
Date: Mon Jun 02 2014 - 12:04:43 EST


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

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