64 строки
1.8 KiB
C
64 строки
1.8 KiB
C
/*
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* Cryptographic API.
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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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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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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 <linux/mm.h>
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#include <asm/scatterlist.h>
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struct scatter_walk {
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struct scatterlist *sg;
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struct page *page;
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void *data;
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unsigned int len_this_page;
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unsigned int len_this_segment;
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unsigned int offset;
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};
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/* Define sg_next is an inline routine now in case we want to change
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scatterlist to a linked list later. */
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static inline struct scatterlist *sg_next(struct scatterlist *sg)
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{
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return sg + 1;
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}
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static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
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struct scatter_walk *walk_out)
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{
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return walk_in->page == walk_out->page &&
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walk_in->offset == walk_out->offset;
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}
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static inline int scatterwalk_across_pages(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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return nbytes > walk->len_this_page;
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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->data += nbytes;
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walk->offset += nbytes;
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walk->len_this_page -= nbytes;
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walk->len_this_segment -= nbytes;
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}
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void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
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int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out);
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void scatterwalk_map(struct scatter_walk *walk, int out);
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void scatterwalk_done(struct scatter_walk *walk, int out, int more);
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#endif /* _CRYPTO_SCATTERWALK_H */
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