// SPDX-License-Identifier: GPL-2.0-or-later/*  * CRC32C *@Article{castagnoli-crc, * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24 *                 and 32 Parity Bits}}, * journal =      IEEE Transactions on Communication, * year =         {1993}, * volume =       {41}, * number =       {6}, * pages =        {}, * month =        {June}, *} * Used by the iSCSI driver, possibly others, and derived from * the iscsi-crc.c module of the linux-iscsi driver at * http://linux-iscsi.sourceforge.net. * * Following the example of lib/crc32, this function is intended to be * flexible and useful for all users.  Modules that currently have their * own crc32c, but hopefully may be able to use this one are: *  net/sctp (please add all your doco to here if you change to *            use this one!) *  <endoflist> * * Copyright (c) 2004 Cisco Systems, Inc. */ #include <crypto/hash.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/crc32c.h> static struct crypto_shash *tfm; u32 crc32c(u32 crc, const void *address, unsigned int length){	SHASH_DESC_ON_STACK(shash, tfm);	u32 ret, *ctx = (u32 *)shash_desc_ctx(shash);	int err; 	shash->tfm = tfm;	*ctx = crc; 	err = crypto_shash_update(shash, address, length);	BUG_ON(err); 	ret = *ctx;	barrier_data(ctx);	return ret;} EXPORT_SYMBOL(crc32c); static int __init libcrc32c_mod_init(void){	tfm = crypto_alloc_shash("crc32c", 0, 0);	return PTR_ERR_OR_ZERO(tfm);} static void __exit libcrc32c_mod_fini(void){	crypto_free_shash(tfm);} const char *crc32c_impl(void){	return crypto_shash_driver_name(tfm);}EXPORT_SYMBOL(crc32c_impl); module_init(libcrc32c_mod_init);module_exit(libcrc32c_mod_fini); MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");MODULE_LICENSE("GPL");MODULE_SOFTDEP("pre: crc32c");