diff options
Diffstat (limited to 'lib/crc-t10dif.c')
-rw-r--r-- | lib/crc-t10dif.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/crc-t10dif.c b/lib/crc-t10dif.c new file mode 100644 index 000000000..dfe6ec17c --- /dev/null +++ b/lib/crc-t10dif.c @@ -0,0 +1,64 @@ +/* + * 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(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(0, buffer, len); + + desc.shash.tfm = crct10dif_tfm; + desc.shash.flags = 0; + *(__u16 *)desc.ctx = 0; + + err = crypto_shash_update(&desc.shash, buffer, len); + BUG_ON(err); + + return *(__u16 *)desc.ctx; +} +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"); |