Staging: dgnc: Use goto for error handling

This patch introduces goto statments for error handling
and in cases where a lock needs to be released.

A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr)

@candidates exists@
identifier f, label;
statement s;
position p1, p2, p3;
@@

  f@p1(...) {
  ...when any

    if@p2(...) {
    ...when any
      s

      return@p3 ...;
    }
  ...when any
  }

@good1 exists@
identifier candidates.f, candidates.label;
statement candidates.s;
position candidates.p1, candidates.p2;
@@

  f@p1(...) {
  ...when any

    if(...) {
    ...when any
      s
      return ...;
    }
    ...when any

    if@p2(...) {...}
  ...when any
 }

@depends on good1@
identifier candidates.f, candidates.label;
position candidates.p1, candidates.p3;
@@

   f@p1(...) {
   ...when any
*  return@p3 ...;
  }

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 12 deletions

diff --git a/drivers/staging/dgnc/dgnc_cls.c b/drivers/staging/dgnc/dgnc_cls.c
index 634d3ea44365..66397d66ee0e 100644
--- a/drivers/staging/dgnc/dgnc_cls.c
+++ b/drivers/staging/dgnc/dgnc_cls.c
@@ -988,22 +988,16 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
 	spin_lock_irqsave(&ch->ch_lock, flags);
 
 	/* No data to write to the UART */
-	if (ch->ch_w_tail == ch->ch_w_head) {
-		spin_unlock_irqrestore(&ch->ch_lock, flags);
-		return;
-	}
+	if (ch->ch_w_tail == ch->ch_w_head)
+		goto exit_unlock;
 
 	/* If port is "stopped", don't send any data to the UART */
 	if ((ch->ch_flags & CH_FORCED_STOP) ||
-				 (ch->ch_flags & CH_BREAK_SENDING)) {
-		spin_unlock_irqrestore(&ch->ch_lock, flags);
-		return;
-	}
+				 (ch->ch_flags & CH_BREAK_SENDING))
+		goto exit_unlock;
 
-	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM))) {
-		spin_unlock_irqrestore(&ch->ch_lock, flags);
-		return;
-	}
+	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
+		goto exit_unlock;
 
 	n = 32;
 
@@ -1053,6 +1047,7 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
 	if (len_written > 0)
 		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 
+exit_unlock:
 	spin_unlock_irqrestore(&ch->ch_lock, flags);
 }