On Thu, Sep 20, 2012 at 05:27:06PM -0700, Tejun Heo wrote: > On Mon, Sep 10, 2012 at 05:22:30PM -0700, Kent Overstreet wrote: > > A bunch of what __blk_queue_bounce() was doing was problematic for the > > immutable bvec work; this cleans that up and the code is quite a bit > > smaller, too. > > > > The __bio_for_each_segment() in copy_to_high_bio_irq() was changed > > because that one's looping over the original bio, not the bounce bio - > > since the bounce code doesn't own that bio the __ version wasn't > > correct. > > Also, I can't understand the above at all. I can think why it > wouldn't be necessary but why is it wrong because bounce code doesn't > own it? Another prep work thing - in current code, it isn't really wrong (slightly inconsistent though). But the idea is that anything that doesn't own the bio shouldn't assume anything about bi_idx; the bounce code should loop over the bio starting from wherever it was when the bio got to the bounce code, not the start of the bio. A later patch makes this clearer - __bio_for_each_segment() gets removed in favor of bio_for_each_segment_all(), and it documents that bio_for_each_segment_all() is only for code that owns the bio. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
