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131 lines
3.2 KiB
131 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* T10 Data Integrity Field CRC16 calculation |
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* |
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* Copyright (c) 2007 Oracle Corporation. All rights reserved. |
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* Written by Martin K. Petersen <[email protected]> |
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*/ |
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#include <linux/types.h> |
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#include <linux/module.h> |
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#include <linux/crc-t10dif.h> |
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#include <linux/err.h> |
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#include <linux/init.h> |
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#include <crypto/hash.h> |
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#include <crypto/algapi.h> |
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#include <linux/static_key.h> |
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#include <linux/notifier.h> |
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static struct crypto_shash __rcu *crct10dif_tfm; |
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static DEFINE_STATIC_KEY_TRUE(crct10dif_fallback); |
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static DEFINE_MUTEX(crc_t10dif_mutex); |
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static struct work_struct crct10dif_rehash_work; |
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static int crc_t10dif_notify(struct notifier_block *self, unsigned long val, void *data) |
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{ |
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struct crypto_alg *alg = data; |
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if (val != CRYPTO_MSG_ALG_LOADED || |
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strcmp(alg->cra_name, CRC_T10DIF_STRING)) |
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return NOTIFY_DONE; |
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schedule_work(&crct10dif_rehash_work); |
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return NOTIFY_OK; |
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} |
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static void crc_t10dif_rehash(struct work_struct *work) |
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{ |
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struct crypto_shash *new, *old; |
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mutex_lock(&crc_t10dif_mutex); |
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old = rcu_dereference_protected(crct10dif_tfm, |
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lockdep_is_held(&crc_t10dif_mutex)); |
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new = crypto_alloc_shash(CRC_T10DIF_STRING, 0, 0); |
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if (IS_ERR(new)) { |
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mutex_unlock(&crc_t10dif_mutex); |
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return; |
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} |
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rcu_assign_pointer(crct10dif_tfm, new); |
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mutex_unlock(&crc_t10dif_mutex); |
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if (old) { |
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synchronize_rcu(); |
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crypto_free_shash(old); |
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} else { |
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static_branch_disable(&crct10dif_fallback); |
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} |
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} |
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static struct notifier_block crc_t10dif_nb = { |
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.notifier_call = crc_t10dif_notify, |
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}; |
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__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len) |
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{ |
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struct { |
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struct shash_desc shash; |
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__u16 crc; |
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} desc; |
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int err; |
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if (static_branch_unlikely(&crct10dif_fallback)) |
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return crc_t10dif_generic(crc, buffer, len); |
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rcu_read_lock(); |
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desc.shash.tfm = rcu_dereference(crct10dif_tfm); |
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desc.crc = crc; |
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err = crypto_shash_update(&desc.shash, buffer, len); |
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rcu_read_unlock(); |
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BUG_ON(err); |
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return desc.crc; |
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} |
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EXPORT_SYMBOL(crc_t10dif_update); |
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__u16 crc_t10dif(const unsigned char *buffer, size_t len) |
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{ |
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return crc_t10dif_update(0, buffer, len); |
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} |
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EXPORT_SYMBOL(crc_t10dif); |
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static int __init crc_t10dif_mod_init(void) |
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{ |
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INIT_WORK(&crct10dif_rehash_work, crc_t10dif_rehash); |
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crypto_register_notifier(&crc_t10dif_nb); |
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crc_t10dif_rehash(&crct10dif_rehash_work); |
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return 0; |
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} |
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static void __exit crc_t10dif_mod_fini(void) |
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{ |
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crypto_unregister_notifier(&crc_t10dif_nb); |
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cancel_work_sync(&crct10dif_rehash_work); |
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crypto_free_shash(rcu_dereference_protected(crct10dif_tfm, 1)); |
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} |
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module_init(crc_t10dif_mod_init); |
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module_exit(crc_t10dif_mod_fini); |
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static int crc_t10dif_transform_show(char *buffer, const struct kernel_param *kp) |
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{ |
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struct crypto_shash *tfm; |
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int len; |
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if (static_branch_unlikely(&crct10dif_fallback)) |
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return sprintf(buffer, "fallback\n"); |
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rcu_read_lock(); |
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tfm = rcu_dereference(crct10dif_tfm); |
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len = snprintf(buffer, PAGE_SIZE, "%s\n", |
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crypto_shash_driver_name(tfm)); |
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rcu_read_unlock(); |
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return len; |
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} |
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module_param_call(transform, NULL, crc_t10dif_transform_show, NULL, 0444); |
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MODULE_DESCRIPTION("T10 DIF CRC calculation (library API)"); |
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MODULE_LICENSE("GPL"); |
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MODULE_SOFTDEP("pre: crct10dif");
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