jbd2: 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/20241202010844.144356-18-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/jbd2/Kconfig b/fs/jbd2/Kconfig
index 4ad2c67f93f153d1ace2b72dacd742f89c6ed41b..9c19e1512101ee719ecd67688defe46f3e436902 100644 (file)
--- a/fs/jbd2/Kconfig
+++ b/fs/jbd2/Kconfig
@@ -2,8 +2,6 @@
 config JBD2
        tristate
        select CRC32
-       select CRYPTO
-       select CRYPTO_CRC32C
        help
          This is a generic journaling layer for block devices that support
          both 32-bit and 64-bit block numbers.  It is currently used by

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 7e49d912b091728ae0e90fb820ee20c755eb465e..d8084b31b3610a446a03089e7564806e8588f2fc 100644 (file)
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1369,20 +1369,12 @@ static int journal_check_superblock(journal_t *journal)
                return err;
        }
 
-       /* Load the checksum driver */
        if (jbd2_journal_has_csum_v2or3_feature(journal)) {
                if (sb->s_checksum_type != JBD2_CRC32C_CHKSUM) {
                        printk(KERN_ERR "JBD2: Unknown checksum type\n");
                        return err;
                }
 
-               journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
-               if (IS_ERR(journal->j_chksum_driver)) {
-                       printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
-                       err = PTR_ERR(journal->j_chksum_driver);
-                       journal->j_chksum_driver = NULL;
-                       return err;
-               }
                /* Check superblock checksum */
                if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
                        printk(KERN_ERR "JBD2: journal checksum error\n");
@@ -1608,8 +1600,6 @@ static journal_t *journal_init_common(struct block_device *bdev,
 
 err_cleanup:
        percpu_counter_destroy(&journal->j_checkpoint_jh_count);
-       if (journal->j_chksum_driver)
-               crypto_free_shash(journal->j_chksum_driver);
        kfree(journal->j_wbuf);
        jbd2_journal_destroy_revoke(journal);
        journal_fail_superblock(journal);
@@ -2191,8 +2181,6 @@ int jbd2_journal_destroy(journal_t *journal)
        iput(journal->j_inode);
        if (journal->j_revoke)
                jbd2_journal_destroy_revoke(journal);
-       if (journal->j_chksum_driver)
-               crypto_free_shash(journal->j_chksum_driver);
        kfree(journal->j_fc_wbuf);
        kfree(journal->j_wbuf);
        kfree(journal);
@@ -2337,27 +2325,15 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
                }
        }
 
-       /* Load the checksum driver if necessary */
-       if ((journal->j_chksum_driver == NULL) &&
-           INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
-               journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
-               if (IS_ERR(journal->j_chksum_driver)) {
-                       printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
-                       journal->j_chksum_driver = NULL;
-                       return 0;
-               }
-               /* Precompute checksum seed for all metadata */
-               journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
-                                                  sizeof(sb->s_uuid));
-       }
-
        lock_buffer(journal->j_sb_buffer);
 
-       /* If enabling v3 checksums, update superblock */
+       /* If enabling v3 checksums, update superblock and precompute seed */
        if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
                sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
                sb->s_feature_compat &=
                        ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
+               journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
+                                                  sizeof(sb->s_uuid));
        }
 
        /* If enabling v1 checksums, downgrade superblock */

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 50f7ea8714bf46cee88b543d35427ef4541f7538..561025b4f3d91da4c07918d79e0ea1a8d1899f7a 100644 (file)
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -28,7 +28,7 @@
 #include <linux/slab.h>
 #include <linux/bit_spinlock.h>
 #include <linux/blkdev.h>
-#include <crypto/hash.h>
+#include <linux/crc32c.h>
 #endif
 
 #define journal_oom_retry 1
@@ -1241,13 +1241,6 @@ struct journal_s
         */
        void *j_private;
 
-       /**
-        * @j_chksum_driver:
-        *
-        * Reference to checksum algorithm driver via cryptoapi.
-        */
-       struct crypto_shash *j_chksum_driver;
-
        /**
         * @j_csum_seed:
         *
@@ -1750,10 +1743,7 @@ static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
 
 static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
 {
-       WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
-                    journal->j_chksum_driver == NULL);
-
-       return journal->j_chksum_driver != NULL;
+       return jbd2_journal_has_csum_v2or3_feature(journal);
 }
 
 static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
@@ -1790,27 +1780,10 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal)
 #define BJ_Reserved    4       /* Buffer is reserved for access by journal */
 #define BJ_Types       5
 
-/* JBD uses a CRC32 checksum */
-#define JBD_MAX_CHECKSUM_SIZE 4
-
 static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
                              const void *address, unsigned int length)
 {
-       DEFINE_RAW_FLEX(struct shash_desc, desc, __ctx,
-               DIV_ROUND_UP(JBD_MAX_CHECKSUM_SIZE,
-                            sizeof(*((struct shash_desc *)0)->__ctx)));
-       int err;
-
-       BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) >
-               JBD_MAX_CHECKSUM_SIZE);
-
-       desc->tfm = journal->j_chksum_driver;
-       *(u32 *)desc->__ctx = crc;
-
-       err = crypto_shash_update(desc, address, length);
-       BUG_ON(err);
-
-       return *(u32 *)desc->__ctx;
+       return crc32c(crc, address, length);
 }
 
 /* Return most recent uncommitted transaction */