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References: <20230718125847.3869700-1-ardb@kernel.org> <ZMOQiPadP2jggZ2i@gondor.apana.org.au>
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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Fri, 28 Jul 2023 11:57:42 +0200
Message-ID: <CAMj1kXFRAhoyRD8mGe4xKZ-xGord2vwPXHCM7O8DPOpYWcgnJw@mail.gmail.com>
Subject: Re: [RFC PATCH 00/21] crypto: consolidate and clean up compression APIs
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     linux-crypto@vger.kernel.org, Eric Biggers <ebiggers@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Haren Myneni <haren@us.ibm.com>,
        Nick Terrell <terrelln@fb.com>,
        Minchan Kim <minchan@kernel.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Jens Axboe <axboe@kernel.dk>,
        Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
        Richard Weinberger <richard@nod.at>,
        David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        qat-linux@intel.com, linuxppc-dev@lists.ozlabs.org,
        linux-mtd@lists.infradead.org, netdev@vger.kernel.org
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On Fri, 28 Jul 2023 at 11:56, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Tue, Jul 18, 2023 at 02:58:26PM +0200, Ard Biesheuvel wrote:
> >
> > Patch #2 removes the support for on-the-fly allocation of destination
> > buffers and scatterlists from the Intel QAT driver. This is never used,
> > and not even implemented by all drivers (the HiSilicon ZIP driver does
> > not support it). The diffstat of this patch makes a good case why the
> > caller should be in charge of allocating the memory, not the driver.
>
> The implementation in qat may not be optimal, but being able to
> allocate memory in the algorithm is a big plus for IPComp at least.
>
> Being able to allocate memory page by page as you decompress
> means that:
>
> 1. We're not affected by memory fragmentation.
> 2. We don't waste memory by always allocating for the worst case.
>

So will IPcomp be able to simply assign those pages to the SKB afterwards?