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

From: Alasdair G Kergon
Date: Tue Sep 18 2012 - 12:32:56 EST


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

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