On Sat, Jun 27 2020 at  3:31am -0400,
Christoph Hellwig [off-list ref] wrote:

bio_uninit is the proper API to clean up a BIO that has been allocated
on stack or inside a structure that doesn't come from the BIO allocator.
Switch dm to use that instead of bio_disassociate_blkg, which really is
an implementation detail.  Note that the bio_uninit calls are also moved
to the two callers of __send_empty_flush, so that they better pair with
the bio_init calls used to initialize them.

Signed-off-by: Christoph Hellwig <hch@lst.de>

I've picked this up as a fix for 5.8

Thanks,
Mike