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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Eric Biggers
41c3aa511e
This backports the current implementation of memcpy_sglist() from
upstream commit 4dffc9bbff.
This function was rewritten twice. The earlier implementations had many
prerequisite commits, while the latest implementation is standalone.
It's much easier to just backport the latest code directly.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
136 lines
3.7 KiB
C
136 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Cryptographic scatter and gather helpers.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
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* Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#ifndef _CRYPTO_SCATTERWALK_H
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#define _CRYPTO_SCATTERWALK_H
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#include <crypto/algapi.h>
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#include <linux/highmem.h>
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#include <linux/mm.h>
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#include <linux/scatterlist.h>
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static inline void scatterwalk_crypto_chain(struct scatterlist *head,
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struct scatterlist *sg, int num)
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{
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if (sg)
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sg_chain(head, num, sg);
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else
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sg_mark_end(head);
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}
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static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
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{
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unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
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unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
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return len_this_page > len ? len : len_this_page;
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}
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static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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unsigned int len_this_page = scatterwalk_pagelen(walk);
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return nbytes > len_this_page ? len_this_page : nbytes;
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}
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static inline void scatterwalk_advance(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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walk->offset += nbytes;
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}
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static inline struct page *scatterwalk_page(struct scatter_walk *walk)
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{
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return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
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}
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static inline void scatterwalk_unmap(void *vaddr)
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{
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kunmap_local(vaddr);
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}
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static inline void scatterwalk_start(struct scatter_walk *walk,
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struct scatterlist *sg)
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{
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walk->sg = sg;
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walk->offset = sg->offset;
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}
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static inline void *scatterwalk_map(struct scatter_walk *walk)
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{
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return kmap_local_page(scatterwalk_page(walk)) +
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offset_in_page(walk->offset);
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}
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static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
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unsigned int more)
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{
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if (out) {
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struct page *page;
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page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
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flush_dcache_page(page);
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}
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if (more && walk->offset >= walk->sg->offset + walk->sg->length)
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scatterwalk_start(walk, sg_next(walk->sg));
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}
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/*
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* Flush the dcache of any pages that overlap the region
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* [offset, offset + nbytes) relative to base_page.
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*
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* This should be called only when ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, to ensure
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* that all relevant code (including the call to sg_page() in the caller, if
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* applicable) gets fully optimized out when !ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE.
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*/
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static inline void __scatterwalk_flush_dcache_pages(struct page *base_page,
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unsigned int offset,
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unsigned int nbytes)
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{
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unsigned int num_pages;
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base_page += offset / PAGE_SIZE;
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offset %= PAGE_SIZE;
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/*
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* This is an overflow-safe version of
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* num_pages = DIV_ROUND_UP(offset + nbytes, PAGE_SIZE).
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*/
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num_pages = nbytes / PAGE_SIZE;
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num_pages += DIV_ROUND_UP(offset + (nbytes % PAGE_SIZE), PAGE_SIZE);
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for (unsigned int i = 0; i < num_pages; i++)
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flush_dcache_page(base_page + i);
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}
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static inline void scatterwalk_done(struct scatter_walk *walk, int out,
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int more)
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{
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if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
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!(walk->offset & (PAGE_SIZE - 1)))
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scatterwalk_pagedone(walk, out, more);
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}
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void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
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size_t nbytes, int out);
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void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
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unsigned int nbytes);
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void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
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unsigned int start, unsigned int nbytes, int out);
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struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
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struct scatterlist *src,
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unsigned int len);
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#endif /* _CRYPTO_SCATTERWALK_H */
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