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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * Cryptographic scatter and gather helpers.4 *5 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>6 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>7 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>8 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>9 */10 11#ifndef _CRYPTO_SCATTERWALK_H12#define _CRYPTO_SCATTERWALK_H13 14#include <crypto/algapi.h>15 16#include <linux/highmem.h>17#include <linux/mm.h>18#include <linux/scatterlist.h>19 20static inline void scatterwalk_crypto_chain(struct scatterlist *head,21 struct scatterlist *sg, int num)22{23 if (sg)24 sg_chain(head, num, sg);25 else26 sg_mark_end(head);27}28 29static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)30{31 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;32 unsigned int len_this_page = offset_in_page(~walk->offset) + 1;33 return len_this_page > len ? len : len_this_page;34}35 36static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,37 unsigned int nbytes)38{39 unsigned int len_this_page = scatterwalk_pagelen(walk);40 return nbytes > len_this_page ? len_this_page : nbytes;41}42 43static inline void scatterwalk_advance(struct scatter_walk *walk,44 unsigned int nbytes)45{46 walk->offset += nbytes;47}48 49static inline struct page *scatterwalk_page(struct scatter_walk *walk)50{51 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);52}53 54static inline void scatterwalk_unmap(void *vaddr)55{56 kunmap_local(vaddr);57}58 59static inline void scatterwalk_start(struct scatter_walk *walk,60 struct scatterlist *sg)61{62 walk->sg = sg;63 walk->offset = sg->offset;64}65 66static inline void *scatterwalk_map(struct scatter_walk *walk)67{68 return kmap_local_page(scatterwalk_page(walk)) +69 offset_in_page(walk->offset);70}71 72static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,73 unsigned int more)74{75 if (out) {76 struct page *page;77 78 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);79 flush_dcache_page(page);80 }81 82 if (more && walk->offset >= walk->sg->offset + walk->sg->length)83 scatterwalk_start(walk, sg_next(walk->sg));84}85 86static inline void scatterwalk_done(struct scatter_walk *walk, int out,87 int more)88{89 if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||90 !(walk->offset & (PAGE_SIZE - 1)))91 scatterwalk_pagedone(walk, out, more);92}93 94void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,95 size_t nbytes, int out);96 97void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,98 unsigned int start, unsigned int nbytes, int out);99 100struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],101 struct scatterlist *src,102 unsigned int len);103 104#endif /* _CRYPTO_SCATTERWALK_H */105