diff options
Diffstat (limited to 'lib/crc64-rocksoft.c')
-rw-r--r-- | lib/crc64-rocksoft.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/lib/crc64-rocksoft.c b/lib/crc64-rocksoft.c new file mode 100644 index 000000000..fc9ae0da5 --- /dev/null +++ b/lib/crc64-rocksoft.c @@ -0,0 +1,126 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/types.h> +#include <linux/module.h> +#include <linux/crc64.h> +#include <linux/err.h> +#include <linux/init.h> +#include <crypto/hash.h> +#include <crypto/algapi.h> +#include <linux/static_key.h> +#include <linux/notifier.h> + +static struct crypto_shash __rcu *crc64_rocksoft_tfm; +static DEFINE_STATIC_KEY_TRUE(crc64_rocksoft_fallback); +static DEFINE_MUTEX(crc64_rocksoft_mutex); +static struct work_struct crc64_rocksoft_rehash_work; + +static int crc64_rocksoft_notify(struct notifier_block *self, unsigned long val, void *data) +{ + struct crypto_alg *alg = data; + + if (val != CRYPTO_MSG_ALG_LOADED || + strcmp(alg->cra_name, CRC64_ROCKSOFT_STRING)) + return NOTIFY_DONE; + + schedule_work(&crc64_rocksoft_rehash_work); + return NOTIFY_OK; +} + +static void crc64_rocksoft_rehash(struct work_struct *work) +{ + struct crypto_shash *new, *old; + + mutex_lock(&crc64_rocksoft_mutex); + old = rcu_dereference_protected(crc64_rocksoft_tfm, + lockdep_is_held(&crc64_rocksoft_mutex)); + new = crypto_alloc_shash(CRC64_ROCKSOFT_STRING, 0, 0); + if (IS_ERR(new)) { + mutex_unlock(&crc64_rocksoft_mutex); + return; + } + rcu_assign_pointer(crc64_rocksoft_tfm, new); + mutex_unlock(&crc64_rocksoft_mutex); + + if (old) { + synchronize_rcu(); + crypto_free_shash(old); + } else { + static_branch_disable(&crc64_rocksoft_fallback); + } +} + +static struct notifier_block crc64_rocksoft_nb = { + .notifier_call = crc64_rocksoft_notify, +}; + +u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len) +{ + struct { + struct shash_desc shash; + u64 crc; + } desc; + int err; + + if (static_branch_unlikely(&crc64_rocksoft_fallback)) + return crc64_rocksoft_generic(crc, buffer, len); + + rcu_read_lock(); + desc.shash.tfm = rcu_dereference(crc64_rocksoft_tfm); + desc.crc = crc; + err = crypto_shash_update(&desc.shash, buffer, len); + rcu_read_unlock(); + + BUG_ON(err); + + return desc.crc; +} +EXPORT_SYMBOL_GPL(crc64_rocksoft_update); + +u64 crc64_rocksoft(const unsigned char *buffer, size_t len) +{ + return crc64_rocksoft_update(0, buffer, len); +} +EXPORT_SYMBOL_GPL(crc64_rocksoft); + +static int __init crc64_rocksoft_mod_init(void) +{ + INIT_WORK(&crc64_rocksoft_rehash_work, crc64_rocksoft_rehash); + crypto_register_notifier(&crc64_rocksoft_nb); + crc64_rocksoft_rehash(&crc64_rocksoft_rehash_work); + return 0; +} + +static void __exit crc64_rocksoft_mod_fini(void) +{ + crypto_unregister_notifier(&crc64_rocksoft_nb); + cancel_work_sync(&crc64_rocksoft_rehash_work); + crypto_free_shash(rcu_dereference_protected(crc64_rocksoft_tfm, 1)); +} + +module_init(crc64_rocksoft_mod_init); +module_exit(crc64_rocksoft_mod_fini); + +static int crc64_rocksoft_transform_show(char *buffer, const struct kernel_param *kp) +{ + struct crypto_shash *tfm; + int len; + + if (static_branch_unlikely(&crc64_rocksoft_fallback)) + return sprintf(buffer, "fallback\n"); + + rcu_read_lock(); + tfm = rcu_dereference(crc64_rocksoft_tfm); + len = snprintf(buffer, PAGE_SIZE, "%s\n", + crypto_shash_driver_name(tfm)); + rcu_read_unlock(); + + return len; +} + +module_param_call(transform, NULL, crc64_rocksoft_transform_show, NULL, 0444); + +MODULE_AUTHOR("Keith Busch <kbusch@kernel.org>"); +MODULE_DESCRIPTION("Rocksoft model CRC64 calculation (library API)"); +MODULE_LICENSE("GPL"); +MODULE_SOFTDEP("pre: crc64"); |