Commit f2b4fa19 authored by Eric Biggers's avatar Eric Biggers
Browse files

ext4: switch to using the crc32c library 



Now that the crc32c() library function directly takes advantage of
architecture-specific optimizations, it is unnecessary to go through the
crypto API.  Just use crc32c().  This is much simpler, and it improves
performance due to eliminating the crypto API overhead.

Reviewed-by: default avatarArd Biesheuvel <ardb@kernel.org>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Acked-by: default avatarTheodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20241202010844.144356-17-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent 38a9a512

fs/ext4/Kconfig

+1 −2
Original line number Diff line number Diff line
@@ -31,8 +31,7 @@ config EXT4_FS 
	select BUFFER_HEAD

	select JBD2

	select CRC16

	select CRYPTO

	select CRYPTO_CRC32C

	select CRC32

	select FS_IOMAP

	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION

	help

fs/ext4/ext4.h

+3 −22
Original line number Diff line number Diff line
@@ -33,7 +33,7 @@ 
#include <linux/blockgroup_lock.h>

#include <linux/percpu_counter.h>

#include <linux/ratelimit.h>

#include <crypto/hash.h>

#include <linux/crc32c.h>

#include <linux/falloc.h>

#include <linux/percpu-rwsem.h>

#include <linux/fiemap.h>
@@ -1662,9 +1662,6 @@ struct ext4_sb_info { 
	/* record the last minlen when FITRIM is called. */

	unsigned long s_last_trim_minblks;



	/* Reference to checksum algorithm driver via cryptoapi */

	struct crypto_shash *s_chksum_driver;



	/* Precomputed FS UUID checksum for seeding other checksums */

	__u32 s_csum_seed;
@@ -2463,19 +2460,7 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize) 
static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,

			      const void *address, unsigned int length)

{

	struct {

		struct shash_desc shash;

		char ctx[4];

	} desc;



	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver)!=sizeof(desc.ctx));



	desc.shash.tfm = sbi->s_chksum_driver;

	*(u32 *)desc.ctx = crc;



	BUG_ON(crypto_shash_update(&desc.shash, address, length));



	return *(u32 *)desc.ctx;

	return crc32c(crc, address, length);

}



#ifdef __KERNEL__
@@ -3276,11 +3261,7 @@ extern int ext4_register_li_request(struct super_block *sb, 


static inline int ext4_has_metadata_csum(struct super_block *sb)

{

	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&

		     !EXT4_SB(sb)->s_chksum_driver);



	return ext4_has_feature_metadata_csum(sb) &&

	       (EXT4_SB(sb)->s_chksum_driver != NULL);

	return ext4_has_feature_metadata_csum(sb);

}



static inline int ext4_has_group_desc_csum(struct super_block *sb)

fs/ext4/super.c

+0 −15
Original line number Diff line number Diff line
@@ -1380,8 +1380,6 @@ static void ext4_put_super(struct super_block *sb) 
	 */

	kobject_put(&sbi->s_kobj);

	wait_for_completion(&sbi->s_kobj_unregister);

	if (sbi->s_chksum_driver)

		crypto_free_shash(sbi->s_chksum_driver);

	kfree(sbi->s_blockgroup_lock);

	fs_put_dax(sbi->s_daxdev, NULL);

	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
@@ -4634,15 +4632,6 @@ static int ext4_init_metadata_csum(struct super_block *sb, struct ext4_super_blo 
	ext4_setup_csum_trigger(sb, EXT4_JTR_ORPHAN_FILE,

				ext4_orphan_file_block_trigger);



	/* Load the checksum driver */

	sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);

	if (IS_ERR(sbi->s_chksum_driver)) {

		int ret = PTR_ERR(sbi->s_chksum_driver);

		ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");

		sbi->s_chksum_driver = NULL;

		return ret;

	}



	/* Check superblock checksum */

	if (!ext4_superblock_csum_verify(sb, es)) {

		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
@@ -5687,9 +5676,6 @@ failed_mount8: __maybe_unused 
	del_timer_sync(&sbi->s_err_report);

	ext4_group_desc_free(sbi);

failed_mount:

	if (sbi->s_chksum_driver)

		crypto_free_shash(sbi->s_chksum_driver);



#if IS_ENABLED(CONFIG_UNICODE)

	utf8_unload(sb->s_encoding);

#endif
@@ -7494,6 +7480,5 @@ static void __exit ext4_exit_fs(void) 
MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");

MODULE_DESCRIPTION("Fourth Extended Filesystem");

MODULE_LICENSE("GPL");

MODULE_SOFTDEP("pre: crc32c");

module_init(ext4_init_fs)

module_exit(ext4_exit_fs)