Commit feb541bf authored by Eric Biggers's avatar Eric Biggers
Browse files

lib/crc64-rocksoft: stop wrapping the crypto API 



Following what was done for the CRC32 and CRC-T10DIF library functions,
get rid of the pointless use of the crypto API and make
crc64_rocksoft_update() call into the library directly.  This is faster
and simpler.

Remove crc64_rocksoft() (the version of the function that did not take a
'crc' argument) since it is unused.

Reviewed-by: default avatarArd Biesheuvel <ardb@kernel.org>
Reviewed-by: default avatar"Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: default avatarKeith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20250130035130.180676-2-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent 2014c95a

block/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ config BLK_DEV_BSGLIB 
config BLK_DEV_INTEGRITY

	bool "Block layer data integrity support"

	select CRC_T10DIF

	select CRC64_ROCKSOFT

	select CRC64

	help

	Some storage devices allow extra information to be

	stored/retrieved to help protect the data.  The block layer

include/linux/crc64.h

+11 −2
Original line number Diff line number Diff line
@@ -12,7 +12,16 @@ 
u64 __pure crc64_be(u64 crc, const void *p, size_t len);

u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len);



u64 crc64_rocksoft(const unsigned char *buffer, size_t len);

u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len);

/**

 * crc64_rocksoft_update - Calculate bitwise Rocksoft CRC64

 * @crc: seed value for computation. 0 for a new CRC calculation, or the

 *	 previous crc64 value if computing incrementally.

 * @p: pointer to buffer over which CRC64 is run

 * @len: length of buffer @p

 */

static inline u64 crc64_rocksoft_update(u64 crc, const u8 *p, size_t len)

{

	return crc64_rocksoft_generic(crc, p, len);

}



#endif /* _LINUX_CRC64_H */

lib/Kconfig

+0 −9
Original line number Diff line number Diff line
@@ -168,15 +168,6 @@ config CRC_T10DIF_ARCH 
	tristate

	default CRC_T10DIF if ARCH_HAS_CRC_T10DIF && CRC_OPTIMIZATIONS



config CRC64_ROCKSOFT

	tristate "CRC calculation for the Rocksoft model CRC64"

	select CRC64

	select CRYPTO

	select CRYPTO_CRC64_ROCKSOFT

	help

	  This option provides a CRC64 API to a registered crypto driver.

	  This is used with the block layer's data integrity subsystem.



config CRC_ITU_T

	tristate "CRC ITU-T V.41 functions"

	help

lib/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -167,7 +167,6 @@ obj-$(CONFIG_CRC64) += crc64.o 
obj-$(CONFIG_CRC4)	+= crc4.o

obj-$(CONFIG_CRC7)	+= crc7.o

obj-$(CONFIG_CRC8)	+= crc8.o

obj-$(CONFIG_CRC64_ROCKSOFT) += crc64-rocksoft.o

obj-$(CONFIG_XXHASH)	+= xxhash.o

obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o

lib/crc64-rocksoft.c

deleted100644 → 0
+0 −126
Original line number Diff line number Diff line 
// 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");