Thread (12 messages) 12 messages, 2 authors, 2012-09-10

Re: [PATCH 0/9] Prep work for immutable bio vecs

From: Tejun Heo <hidden>
Date: 2012-09-08 19:41:24
Also in: dm-devel, lkml

Hello, Kent.

On Fri, Sep 07, 2012 at 03:59:11PM -0700, Kent Overstreet wrote:
Random assortment of refactoring and trivial cleanups.

Immutable bio vecs and efficient bio splitting require auditing and removing
pretty much all bi_idx uses, among other things.

The reason is that with immutable bio vecs we can't use the bvec array
directly; if we have a partially completed bvec, that'll be indicated with a
field in struct bvec_iter (which gets embedded in struct bio) - bi_bvec_done.

bio_for_each_segments() will handle this transparently, so code needs to be
converted to use it or some other generic accessor.

Also, bio splitting means that when a driver gets a bio, bi_idx and
bi_bvec_done may both be nonzero. Again, just need to use generic accessors.
There are three pending patchsets and I don't know how they're
supposed to come together.  Please explain on which tree the patches
are based and how they stack and preferably provide a git branch.

Thanks.

-- 
tejun
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