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df91f56adc
This function returns a string with the currently in-use implementation of the crc32c algorithm, i.e crc32c-generic (for unoptimised, generic implementation) or crc32c-intel for the sse optimised version. This will be used by btrfs. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> [ use crypto_shash_driver_name as suggested by Herbert ] Signed-off-by: David Sterba <dsterba@suse.com>
87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*
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* CRC32C
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*@Article{castagnoli-crc,
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* author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
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* title = {{Optimization of Cyclic Redundancy-Check Codes with 24
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* and 32 Parity Bits}},
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* journal = IEEE Transactions on Communication,
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* year = {1993},
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* volume = {41},
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* number = {6},
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* pages = {},
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* month = {June},
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*}
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* Used by the iSCSI driver, possibly others, and derived from the
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* the iscsi-crc.c module of the linux-iscsi driver at
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* http://linux-iscsi.sourceforge.net.
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*
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* Following the example of lib/crc32, this function is intended to be
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* flexible and useful for all users. Modules that currently have their
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* own crc32c, but hopefully may be able to use this one are:
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* net/sctp (please add all your doco to here if you change to
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* use this one!)
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* <endoflist>
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*
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* Copyright (c) 2004 Cisco Systems, Inc.
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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/hash.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/crc32c.h>
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static struct crypto_shash *tfm;
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u32 crc32c(u32 crc, const void *address, unsigned int length)
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{
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SHASH_DESC_ON_STACK(shash, tfm);
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u32 ret, *ctx = (u32 *)shash_desc_ctx(shash);
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int err;
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shash->tfm = tfm;
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shash->flags = 0;
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*ctx = crc;
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err = crypto_shash_update(shash, address, length);
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BUG_ON(err);
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ret = *ctx;
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barrier_data(ctx);
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return ret;
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}
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EXPORT_SYMBOL(crc32c);
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static int __init libcrc32c_mod_init(void)
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{
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tfm = crypto_alloc_shash("crc32c", 0, 0);
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return PTR_ERR_OR_ZERO(tfm);
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}
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static void __exit libcrc32c_mod_fini(void)
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{
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crypto_free_shash(tfm);
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}
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const char *crc32c_impl(void)
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{
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return crypto_shash_driver_name(tfm);
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}
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EXPORT_SYMBOL(crc32c_impl);
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module_init(libcrc32c_mod_init);
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module_exit(libcrc32c_mod_fini);
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MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
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MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
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MODULE_LICENSE("GPL");
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MODULE_SOFTDEP("pre: crc32c");
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