jbd2: jbd2_get_transaction does not need to return a value

In jbd2_get_transaction, a new transaction is initialized,
and set to the j_running_transaction. No need for a return
value, so remove it.

Also, adjust some comments to match the actual operation
of this function.

Signed-off-by: Liu Song <liu.song11@zte.com.cn>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

fs/jbd2/transaction.c

@@ -63,7 +63,7 @@ void jbd2_journal_free_transaction(transaction_t *transaction)
 /*
  * jbd2_get_transaction: obtain a new transaction_t object.
  *
- * Simply allocate and initialise a new transaction.  Create it in
+ * Simply initialise a new transaction. Initialize it in
  * RUNNING state and add it to the current journal (which should not
  * have an existing running transaction: we only make a new transaction
  * once we have started to commit the old one).
@@ -75,8 +75,8 @@ void jbd2_journal_free_transaction(transaction_t *transaction)
  *
  */
 
-static transaction_t *
-jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
+static void jbd2_get_transaction(journal_t *journal,
+				transaction_t *transaction)
 {
 	transaction->t_journal = journal;
 	transaction->t_state = T_RUNNING;
@@ -100,8 +100,6 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
 	transaction->t_max_wait = 0;
 	transaction->t_start = jiffies;
 	transaction->t_requested = 0;
-
-	return transaction;
 }
 
 /*