forked from luck/tmp_suning_uos_patched
2ee732d574
Nothing bad will happen even if sg->length is zero, so there is no point in keeping this BUG_ON in scatterwalk_start. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/*
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* Cryptographic API.
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*
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* Cipher operations.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* 2002 Adam J. Richter <adam@yggdrasil.com>
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* 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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#include <crypto/scatterwalk.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/scatterlist.h>
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static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
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{
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void *src = out ? buf : sgdata;
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void *dst = out ? sgdata : buf;
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memcpy(dst, src, nbytes);
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}
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void scatterwalk_start(struct scatter_walk *walk, 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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EXPORT_SYMBOL_GPL(scatterwalk_start);
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void *scatterwalk_map(struct scatter_walk *walk)
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{
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return kmap_atomic(scatterwalk_page(walk)) +
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offset_in_page(walk->offset);
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}
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EXPORT_SYMBOL_GPL(scatterwalk_map);
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static 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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/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
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* PageSlab cannot be optimised away per se due to
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* use of volatile pointer.
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*/
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if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
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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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void scatterwalk_done(struct scatter_walk *walk, int out, 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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EXPORT_SYMBOL_GPL(scatterwalk_done);
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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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{
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for (;;) {
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unsigned int len_this_page = scatterwalk_pagelen(walk);
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u8 *vaddr;
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if (len_this_page > nbytes)
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len_this_page = nbytes;
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if (out != 2) {
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vaddr = scatterwalk_map(walk);
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memcpy_dir(buf, vaddr, len_this_page, out);
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scatterwalk_unmap(vaddr);
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}
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scatterwalk_advance(walk, len_this_page);
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if (nbytes == len_this_page)
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break;
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buf += len_this_page;
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nbytes -= len_this_page;
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scatterwalk_pagedone(walk, out & 1, 1);
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}
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}
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EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
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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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{
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struct scatter_walk walk;
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struct scatterlist tmp[2];
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if (!nbytes)
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return;
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sg = scatterwalk_ffwd(tmp, sg, start);
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if (sg_page(sg) == virt_to_page(buf) &&
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sg->offset == offset_in_page(buf))
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return;
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scatterwalk_start(&walk, sg);
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scatterwalk_copychunks(buf, &walk, nbytes, out);
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scatterwalk_done(&walk, out, 0);
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}
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EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
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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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{
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for (;;) {
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if (!len)
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return src;
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if (src->length > len)
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break;
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len -= src->length;
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src = sg_next(src);
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}
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sg_init_table(dst, 2);
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sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
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scatterwalk_crypto_chain(dst, sg_next(src), 0, 2);
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return dst;
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}
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EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
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