Re: [dm-devel] [PATCH v10 1/8] block: Generalized bio pool freeing

[Alasdair G Kergon <agk redhat com>]

On Mon, Sep 17, 2012 at 01:51:39PM -0700, Kent Overstreet wrote:
> That isn't a very good patch - it says it's clearing bi_end_io as a
> precaution, but as a precaution to what?
 
As a precaution against the endio function being called an extra time by
mistake if a stray reference remains after the bio has been freed.
Wipe this field when dm frees it.  Defensive programming, basically,
in response to a tricky bug he had to deal with.

Alasdair