[dm-devel] [PATCH v6 11/13] block: Rework bio_pair_split()

[Martin K. Petersen]

>>>>> "Tejun" == Tejun Heo <tj at kernel.org> writes:

Tejun> I complained about this in the last posting and in the previous
Tejun> patch.  Please respond.  Martin, are you okay with these
Tejun> integrity changes?

I missed the first several iterations of all this while I was out on
vacation. I'll have to try to wrap my head around the new approach.

However, I'm not sure I like the overall approach of the new splitting.
Instead of all this cloning, slicing and dicing of bio_vecs I'd rather
we bit the bullet and had an offset + length for the vector inside each
bio. That way we could keep the bio_vec immutable and make clones more
lightweight since their vecs would always point to the parent. This also
makes it trivial to split I/Os in the stacking drivers and removes evils
in the partial completion code path. It would also allow to sever the
ties between "size of block range operated on" vs. bi_size which we need
for copy offload, discard, etc.

-- 
Martin K. Petersen	Oracle Linux Engineering