Messages in this thread | | | Date | Wed, 15 Feb 2017 22:12:08 +0000 | From | Giovanni Cabiddu <> | Subject | Re: [RFC PATCH v1 1/1] mm: zswap - Add crypto acomp/scomp framework support |
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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
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