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From:   Lukasz Stelmach <l.stelmach@samsung.com>
To:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        linux-crypto@vger.kernel.org
Subject: xor_blocks() assumptions
Date:   Mon, 02 Jan 2023 23:44:35 +0100
Message-ID: <dleftjk024o8to.fsf%l.stelmach@samsung.com>
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Hi,

I am researching possibility to use xor_blocks() in crypto_xor() and
crypto_xor_cpy(). What I've found already is that different architecture
dependent xor functions work on different blocks between 16 and 512
(Intel AVX) bytes long. There is a hint in the comment for
async_xor_offs() that src_cnt (as passed to do_sync_xor_offs()) counts
pages. Thus, it is assumed, that the smallest chunk xor_blocks() gets is
a single page. Am I right?

Do you think adding block_len field to struct xor_block_template (and
maybe some information about required alignment) and using it to call
do_2 from crypto_xor() may work? I am thinking especially about disk
encryption where sectors of 512~4096 are handled.

Kind regards,
=2D-=20
=C5=81ukasz Stelmach
Samsung R&D Institute Poland
Samsung Electronics

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