f2fs: clean up hash codes

f2fs_chksum and f2fs_crc32 use the same 'crc32' crypto engine, also
their implementation are almost the same, except with different
shash description context.

Introduce __f2fs_crc32 to wrap the common codes, and reuse it in
f2fs_chksum and f2fs_crc32.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -1255,33 +1255,7 @@ static inline bool is_idle(struct f2fs_sb_info *sbi)
 /*
  * Inline functions
  */
-static inline u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address,
-			   unsigned int length)
-{
-	SHASH_DESC_ON_STACK(shash, sbi->s_chksum_driver);
-	u32 *ctx = (u32 *)shash_desc_ctx(shash);
-	u32 retval;
-	int err;
-
-	shash->tfm = sbi->s_chksum_driver;
-	shash->flags = 0;
-	*ctx = F2FS_SUPER_MAGIC;
-
-	err = crypto_shash_update(shash, address, length);
-	BUG_ON(err);
-
-	retval = *ctx;
-	barrier_data(ctx);
-	return retval;
-}
-
-static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc,
-				  void *buf, size_t buf_size)
-{
-	return f2fs_crc32(sbi, buf, buf_size) == blk_crc;
-}
-
-static inline u32 f2fs_chksum(struct f2fs_sb_info *sbi, u32 crc,
+static inline u32 __f2fs_crc32(struct f2fs_sb_info *sbi, u32 crc,
 			      const void *address, unsigned int length)
 {
 	struct {
@@ -1302,6 +1276,24 @@ static inline u32 f2fs_chksum(struct f2fs_sb_info *sbi, u32 crc,
 	return *(u32 *)desc.ctx;
 }
 
+static inline u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address,
+			   unsigned int length)
+{
+	return __f2fs_crc32(sbi, F2FS_SUPER_MAGIC, address, length);
+}
+
+static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc,
+				  void *buf, size_t buf_size)
+{
+	return f2fs_crc32(sbi, buf, buf_size) == blk_crc;
+}
+
+static inline u32 f2fs_chksum(struct f2fs_sb_info *sbi, u32 crc,
+			      const void *address, unsigned int length)
+{
+	return __f2fs_crc32(sbi, crc, address, length);
+}
+
 static inline struct f2fs_inode_info *F2FS_I(struct inode *inode)
 {
 	return container_of(inode, struct f2fs_inode_info, vfs_inode);