Re: [RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework support

From	Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework support
Date	2017-02-15 23:20 +0100
Message-ID	<tbg5z-5Kb-7@gated-at.bofh.it> (permalink)
References	<taNwB-3Fj-7@gated-at.bofh.it> <taNwB-3Fj-5@gated-at.bofh.it> <taO9j-47Q-13@gated-at.bofh.it> <tbg5z-5Kb-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Wed, Feb 15, 2017 at 07:27:30PM +0530, Narayana Prasad Athreya wrote:
> > I assume all of these crypto_acomp_[compress|decompress] calls are
> > actually synchronous,
> > not asynchronous as the name suggests.  Otherwise, this would blow up
> > quite spectacularly
> > since all the resources we use in the call get derefed/unmapped below.
> > 
> > Could an async algorithm be implement/used that would break this assumption?
> 
> The callback is set to NULL using acomp_request_set_callback(). This implies
> synchronous mode of operation. So the underlying implementation must
> complete the operation synchronously.
This assumption is not correct. An asynchronous implementation, when
it finishes processing a request, will call acomp_request_complete() which
in turn calls the callback.
If the callback is set to NULL, this function will dereference a NULL
pointer.

Regards,

-- 
Giovanni

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework support Mahipal Challa <mahipalreddy2006@gmail.com> - 2017-02-14 16:50 +0100
  Re: [RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework support Seth Jennings <sjenning@redhat.com> - 2017-02-14 17:30 +0100
    Re: [RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework  support Giovanni Cabiddu <giovanni.cabiddu@intel.com> - 2017-02-15 23:20 +0100

csiph-web