On Wed, Dec 21, 2016 at 03:19:15PM -0800, Linus Torvalds wrote:
> Looking around a bit, the only even halfway suspicious scatterlist
> initialization thing I see is commit f9d03f96b988 ("block: improve
> handling of the magic discard payload") which used to have a magic
> hack wrt !bio->bi_vcnt, and that got removed. See __blk_bios_map_sg(),
> now it does __blk_bvec_map_sg() instead.But that check was only for discard (and discard-like) bios which had the maic single page that sometimes was unused attached. For "normal" bios the for_each_segment loop iterates over bi_vcnt, so it will be ignored anyway. That being said both I and the lists got CCed halfway through the thread and I haven't seen the original report, so I'm not really sure what's going on here anyway.
