Re: [PATCH 04/13] blk-crypto: decrypt one data unit per crypto request

[sashiko-bot@kernel.org]

> __blk_crypto_fallback_decrypt_bio() decrypts the bio one bio_vec at a
> time: it walks the bio_vecs with __bio_for_each_segment(), requires each
> bio_vec to be data unit aligned and a multiple of the data unit size, and
> decrypts every data unit in it with a scatterlist that covers the whole
> bio_vec.
> 
> That requires a data unit to be contiguous in memory, and cannot express
> a data unit that spans more than a page.  In preparation for supporting
> such data units, collect the bio_vecs that make up one data unit in the
> new blk_crypto_du_bvecs(), and decrypt the data unit with a single crypto
> request whose scatterlist spans those bio_vecs.
> 
> Add a struct blk_crypto_du_ctx to describe one data unit, with
> blk_crypto_du_ctx_init() to initialize it and blk_crypto_du_bvecs() to
> fill in its bio_vecs.  The array that holds them is sized for one
> bio_vec and lives on the stack, so a data unit that needs more than
> one bio_vec is rejected with BLK_STS_INVAL for now.
> 
> Also add a blk_crypto_crypt_du() helper that en/decrypts one data unit.
> Only the decryption path uses it in this patch; the encryption path will
> be restructured the same way in a follow-up patch, with the bounce page
> scatterlist as the destination.
> 
> No functional change intended.
> 
> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261011170958.1759230-1-libaokun@linux.alibaba.com?part=4