[PATCH v2 17/18] f2fs: switch to using the crc32 library

[Eric Biggers]

From: Eric Biggers <ebiggers at google.com>

Now that the crc32() library function takes advantage of
architecture-specific optimizations, it is unnecessary to go through the
crypto API.  Just use crc32().  This is much simpler, and it improves
performance due to eliminating the crypto API overhead.

Reviewed-by: Ard Biesheuvel <ardb at kernel.org>
Signed-off-by: Eric Biggers <ebiggers at google.com>
---
 fs/f2fs/Kconfig |  3 +--
 fs/f2fs/f2fs.h  | 19 +------------------
 fs/f2fs/super.c | 15 ---------------
 3 files changed, 2 insertions(+), 35 deletions(-)

diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index 68a1e23e1557..5916a02fb46d 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -2,12 +2,11 @@
 config F2FS_FS
 	tristate "F2FS filesystem support"
 	depends on BLOCK
 	select BUFFER_HEAD
 	select NLS
-	select CRYPTO
-	select CRYPTO_CRC32
+	select CRC32
 	select F2FS_FS_XATTR if FS_ENCRYPTION
 	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
 	select FS_IOMAP
 	select LZ4_COMPRESS if F2FS_FS_LZ4
 	select LZ4_DECOMPRESS if F2FS_FS_LZ4
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 33f5449dc22d..1fc5c2743c8d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1761,13 +1761,10 @@ struct f2fs_sb_info {
 
 	/* For write statistics */
 	u64 sectors_written_start;
 	u64 kbytes_written;
 
-	/* Reference to checksum algorithm driver via cryptoapi */
-	struct crypto_shash *s_chksum_driver;
-
 	/* Precomputed FS UUID checksum for seeding other checksums */
 	__u32 s_chksum_seed;
 
 	struct workqueue_struct *post_read_wq;	/* post read workqueue */
 
@@ -1941,25 +1938,11 @@ static inline unsigned int f2fs_time_to_wait(struct f2fs_sb_info *sbi,
  * Inline functions
  */
 static inline u32 __f2fs_crc32(struct f2fs_sb_info *sbi, u32 crc,
 			      const void *address, unsigned int length)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[4];
-	} desc;
-	int err;
-
-	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != sizeof(desc.ctx));
-
-	desc.shash.tfm = sbi->s_chksum_driver;
-	*(u32 *)desc.ctx = crc;
-
-	err = crypto_shash_update(&desc.shash, address, length);
-	BUG_ON(err);
-
-	return *(u32 *)desc.ctx;
+	return crc32(crc, address, length);
 }
 
 static inline u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address,
 			   unsigned int length)
 {
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 87ab5696bd48..003d3bcb0caa 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1670,12 +1670,10 @@ static void f2fs_put_super(struct super_block *sb)
 
 	f2fs_destroy_post_read_wq(sbi);
 
 	kvfree(sbi->ckpt);
 
-	if (sbi->s_chksum_driver)
-		crypto_free_shash(sbi->s_chksum_driver);
 	kfree(sbi->raw_super);
 
 	f2fs_destroy_page_array_cache(sbi);
 	f2fs_destroy_xattr_caches(sbi);
 #ifdef CONFIG_QUOTA
@@ -4419,19 +4417,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		INIT_LIST_HEAD(&sbi->inode_list[i]);
 		spin_lock_init(&sbi->inode_lock[i]);
 	}
 	mutex_init(&sbi->flush_lock);
 
-	/* Load the checksum driver */
-	sbi->s_chksum_driver = crypto_alloc_shash("crc32", 0, 0);
-	if (IS_ERR(sbi->s_chksum_driver)) {
-		f2fs_err(sbi, "Cannot load crc32 driver.");
-		err = PTR_ERR(sbi->s_chksum_driver);
-		sbi->s_chksum_driver = NULL;
-		goto free_sbi;
-	}
-
 	/* set a block size */
 	if (unlikely(!sb_set_blocksize(sb, F2FS_BLKSIZE))) {
 		f2fs_err(sbi, "unable to set blocksize");
 		goto free_sbi;
 	}
@@ -4872,12 +4861,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 	fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy);
 	kvfree(options);
 free_sb_buf:
 	kfree(raw_super);
 free_sbi:
-	if (sbi->s_chksum_driver)
-		crypto_free_shash(sbi->s_chksum_driver);
 	kfree(sbi);
 	sb->s_fs_info = NULL;
 
 	/* give only one another chance */
 	if (retry_cnt > 0 && skip_recovery) {
@@ -5080,7 +5067,5 @@ module_init(init_f2fs_fs)
 module_exit(exit_f2fs_fs)
 
 MODULE_AUTHOR("Samsung Electronics's Praesto Team");
 MODULE_DESCRIPTION("Flash Friendly File System");
 MODULE_LICENSE("GPL");
-MODULE_SOFTDEP("pre: crc32");
-
-- 
2.47.0