/* * T10 Data Integrity Field CRC16 calculation * * Copyright (c) 2007 Oracle Corporation. All rights reserved. * Written by Martin K. Petersen <martin.petersen@oracle.com> * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include <linux/types.h> #include <linux/module.h> #include <linux/crc-t10dif.h> #include <linux/err.h> #include <linux/init.h> #include <crypto/hash.h> #include <linux/static_key.h> static struct crypto_shash *crct10dif_tfm; static struct static_key crct10dif_fallback __read_mostly; __u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len) { struct { struct shash_desc shash; char ctx[2]; } desc; int err; if (static_key_false(&crct10dif_fallback)) return crc_t10dif_generic(crc, buffer, len); desc.shash.tfm = crct10dif_tfm; desc.shash.flags = 0; *(__u16 *)desc.ctx = crc; err = crypto_shash_update(&desc.shash, buffer, len); BUG_ON(err); return *(__u16 *)desc.ctx; } EXPORT_SYMBOL(crc_t10dif_update); __u16 crc_t10dif(const unsigned char *buffer, size_t len) { return crc_t10dif_update(0, buffer, len); } EXPORT_SYMBOL(crc_t10dif); static int __init crc_t10dif_mod_init(void) { crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0); if (IS_ERR(crct10dif_tfm)) { static_key_slow_inc(&crct10dif_fallback); crct10dif_tfm = NULL; } return 0; } static void __exit crc_t10dif_mod_fini(void) { crypto_free_shash(crct10dif_tfm); } module_init(crc_t10dif_mod_init); module_exit(crc_t10dif_mod_fini); MODULE_DESCRIPTION("T10 DIF CRC calculation"); MODULE_LICENSE("GPL"); MODULE_SOFTDEP("pre: crct10dif");