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https://github.com/torvalds/linux
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2062c5b6da
Change the crypto 842 compression alg to use the software 842 compression and decompression library. Add the crypto driver_name as "842-generic". Remove the fallback to LZO compression. Previously, this crypto compression alg attemped 842 compression using PowerPC hardware, and fell back to LZO compression and decompression if the 842 PowerPC hardware was unavailable or failed. This should not fall back to any other compression method, however; users of this crypto compression alg can fallback if desired, and transparent fallback tricks callers into thinking they are getting 842 compression when they actually get LZO compression - the failure of the 842 hardware should not be transparent to the caller. The crypto compression alg for a hardware device also should not be located in crypto/ so this is now a software-only implementation that uses the 842 software compression/decompression library. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
/*
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* Cryptographic API for the 842 software compression algorithm.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Copyright (C) IBM Corporation, 2011-2015
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*
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* Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
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* Seth Jennings <sjenning@linux.vnet.ibm.com>
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*
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* Rewrite: Dan Streetman <ddstreet@ieee.org>
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*
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* This is the software implementation of compression and decompression using
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* the 842 format. This uses the software 842 library at lib/842/ which is
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* only a reference implementation, and is very, very slow as compared to other
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* software compressors. You probably do not want to use this software
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* compression. If you have access to the PowerPC 842 compression hardware, you
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* want to use the 842 hardware compression interface, which is at:
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* drivers/crypto/nx/nx-842-crypto.c
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/crypto.h>
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#include <linux/sw842.h>
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struct crypto842_ctx {
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char wmem[SW842_MEM_COMPRESS]; /* working memory for compress */
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};
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static int crypto842_compress(struct crypto_tfm *tfm,
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const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen)
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{
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struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
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return sw842_compress(src, slen, dst, dlen, ctx->wmem);
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}
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static int crypto842_decompress(struct crypto_tfm *tfm,
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const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen)
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{
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return sw842_decompress(src, slen, dst, dlen);
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}
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static struct crypto_alg alg = {
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.cra_name = "842",
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.cra_driver_name = "842-generic",
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.cra_priority = 100,
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.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
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.cra_ctxsize = sizeof(struct crypto842_ctx),
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.cra_module = THIS_MODULE,
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.cra_u = { .compress = {
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.coa_compress = crypto842_compress,
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.coa_decompress = crypto842_decompress } }
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};
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static int __init crypto842_mod_init(void)
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{
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return crypto_register_alg(&alg);
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}
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module_init(crypto842_mod_init);
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static void __exit crypto842_mod_exit(void)
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{
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crypto_unregister_alg(&alg);
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}
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module_exit(crypto842_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("842 Software Compression Algorithm");
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MODULE_ALIAS_CRYPTO("842");
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MODULE_ALIAS_CRYPTO("842-generic");
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MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
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