[PATCH v3 05/19] crypto: scatterwalk - add scatterwalk_get_sglist()
From: Eric Biggers <ebiggers@kernel.org>
Date: 2025-02-19 18:24:28
Also in:
linux-crypto, lkml
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
From: Eric Biggers <redacted> Add a function that creates a scatterlist that represents the remaining data in a walk. This will be used to replace chain_to_walk() in net/tls/tls_device_fallback.c so that it will no longer need to reach into the internals of struct scatter_walk. Cc: Boris Pismenny <borisp@nvidia.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Eric Biggers <redacted> --- include/crypto/scatterwalk.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 1689ecd7ddafa..f6262d05a3c75 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h@@ -67,10 +67,27 @@ static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, static inline struct page *scatterwalk_page(struct scatter_walk *walk) { return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); } +/* + * Create a scatterlist that represents the remaining data in a walk. Uses + * chaining to reference the original scatterlist, so this uses at most two + * entries in @sg_out regardless of the number of entries in the original list. + * Assumes that sg_init_table() was already done. + */ +static inline void scatterwalk_get_sglist(struct scatter_walk *walk, + struct scatterlist sg_out[2]) +{ + if (walk->offset >= walk->sg->offset + walk->sg->length) + scatterwalk_start(walk, sg_next(walk->sg)); + sg_set_page(sg_out, sg_page(walk->sg), + walk->sg->offset + walk->sg->length - walk->offset, + walk->offset); + scatterwalk_crypto_chain(sg_out, sg_next(walk->sg), 2); +} + static inline void scatterwalk_unmap(void *vaddr) { kunmap_local(vaddr); }
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2.48.1