On Thu, Jan 30, 2020 at 07:23:42PM -0800, Bijan Mottahedeh wrote: > Get a reference to a bio, so it won't be freed if end_io() gets to > it before submit_io() returns. Defer the release of the first bio > in a mult-bio request until the last end_io() since the first bio is > embedded in the dio structure and must therefore persist through an > entire multi-bio request. Can you explain the issue a little more? The initial bio is embedded into the dio, and will have a reference until the bio_put call at the end of the function, so we can't have a race for that one and won't ever need the refcount for the single bio case. Avoiding the atomic is pretty important for aio/uring performance.
