On lines 3430-3434, bh has been assured to be non-null:
    cn = get_journal_hash_dev(sb, journal->j_hash_table, blocknr);
    if (!cn || !cn->bh) {
        return ret;
    }
    bh = cn->bh;

Thus, the check of bh on line 3447 is unnecessary and can be removed.
Thank Andrew Morton for good advice.

Link: http://lkml.kernel.org/r/20190727084019.11307-1-baijiaju1990@gmail.comSigned-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Cc: Bharath Vedartham <linux.bhar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>