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: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20241202010844.144356-17-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index e20d59221fc05b162bb72ebabdefb2b83d3cb26d..c9ca41d91a6c1626b111ccb483d9feff216dcd0f 100644 (file)
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -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

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 74f2071189b2438916fc2792222178b64c50af3e..4e7de7eaa374a0cd404318f6a8a452e64c6ea95c 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 785809f33ff4a9bda0dcf3f03092fb7816c5b49d..fdf4817a7dbc4ac1c2405a438b1866bf82bdbe47 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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_mount3:
        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)