On 11/30/18 1:38 AM, Christoph Hellwig wrote:

I like the idea, but I don't think it is correct as-is.  We can't just
move the blkdev_bio_dirty_release for the last bio into the caller, as
the completion order that decrements the refcount might have different
ordering.

Ugh yeah, not sure why I forgot about the multi case for that one.

Something like the simpler patch below might archive your goal, though:

That does look cleaner. Let me run it through some testing just to
ensure we don't leak or use-after-free.

-- 
Jens Axboe