5c64097aa0
This patch prepares the scatterwalk code for use by the new block cipher type. Firstly it halves the size of scatter_walk on 32-bit platforms. This is important as we allocate at least two of these objects on the stack for each block cipher operation. It also exports the symbols since the block cipher code can be built as a module. Finally there is a hack in scatterwalk_unmap that relies on progress being made. Unfortunately, for hardware crypto we can't guarantee progress to be made since the hardware can fail. So this also gets rid of the hack by not advancing the address returned by scatterwalk_map. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
80 lines
2.3 KiB
C
80 lines
2.3 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 <linux/scatterlist.h>
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#include "internal.h"
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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 unsigned long 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->sg->page - walk_out->sg->page) << PAGE_SHIFT) +
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(int)(walk_in->offset - walk_out->offset));
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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 unsigned int scatterwalk_aligned(struct scatter_walk *walk,
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unsigned int alignmask)
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{
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return !(walk->offset & alignmask);
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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 walk->sg->page + (walk->offset >> PAGE_SHIFT);
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}
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static inline void scatterwalk_unmap(void *vaddr, int out)
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{
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crypto_kunmap(vaddr, out);
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}
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void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
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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 *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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