Re: [PATCH V4 10/12] block: call __bio_free in bio_endio

Christoph Hellwig
2017-06-28T21:29:17Z

On Wed, Jun 28, 2017 at 09:30:00AM -0700, Shaohua Li wrote:
> From: Shaohua Li <shli@fb.com>
>
> bio_free isn't a good place to free cgroup/integrity info. There are a
> lot of cases bio is allocated in special way (for example, in stack) and
> never gets called by bio_put hence bio_free, we are leaking memory. This
> patch moves the free to bio endio, which should be called anyway. The
> __bio_free call in bio_free is kept, in case the bio never gets called
> bio endio.
>
> This assumes ->bi_end_io() doesn't access cgroup/integrity info, which
> seems true in my audit. Otherwise, we probably must add a flag to
> distinguish if bio will be called by bio_put.

bio_integrity_endio -> bio_integrity_verify_fn -> bio_integrity_process
access the integrity data, so I don't think this works as-is.