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Date:   Fri, 28 Jul 2023 17:55:20 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     linux-crypto@vger.kernel.org, Eric Biggers <ebiggers@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Haren Myneni <haren@us.ibm.com>,
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        Minchan Kim <minchan@kernel.org>,
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        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>,
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Subject: Re: [RFC PATCH 00/21] crypto: consolidate and clean up compression
 APIs
Message-ID: <ZMOQiPadP2jggZ2i@gondor.apana.org.au>
References: <20230718125847.3869700-1-ardb@kernel.org>
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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.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt