Blackfin Serial Driver: fix bug - use mod_timer to replace only add_timer.

http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=4045
If adding timer in both timer handler and rx interrupt, a timer may be
added when it is till in the pending list.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 47ca7b0267df..5f55534a290b 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -506,8 +506,7 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
                 uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
         }
 
-        uart->rx_dma_timer.expires = jiffies + DMA_RX_FLUSH_JIFFIES;
-        add_timer(&(uart->rx_dma_timer));
+        mod_timer(&(uart->rx_dma_timer), jiffies + DMA_RX_FLUSH_JIFFIES);
 }
 
 static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
@@ -550,9 +549,7 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id)
         clear_dma_irqstat(uart->rx_dma_channel);
         spin_unlock(&uart->port.lock);
 
-        del_timer(&(uart->rx_dma_timer));
-        uart->rx_dma_timer.expires = jiffies;
-        add_timer(&(uart->rx_dma_timer));
+        mod_timer(&(uart->rx_dma_timer), jiffies);
 
         return IRQ_HANDLED;
 }