serial: tegra: use locked version for tty buffer copy

Use locked version of the string insert API to tty buffer
to avoid any race condition.

bug 200042027

Change-Id: I57ae167725ecbe0777ecbab89be0fb90fa90e5c7
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Reviewed-on: http://git-master/r/654458
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index c4a68dfa158f24c4e522b73f3dc3f8bc9ddd114f..0aa7c6d4a1c92362e922e7e2d0dce05baf12be5e 100644 (file)
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -510,6 +510,8 @@ static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
 static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
                struct tty_port *tty)
 {
+       int copied;
+
        do {
                char flag = TTY_NORMAL;
                unsigned long lsr = 0;
@@ -523,8 +525,12 @@ static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
                ch = (unsigned char) tegra_uart_read(tup, UART_RX);
                tup->uport.icount.rx++;
 
-               if (!uart_handle_sysrq_char(&tup->uport, ch) && tty)
-                       tty_insert_flip_char(tty, ch, flag);
+               if (!uart_handle_sysrq_char(&tup->uport, ch) && tty) {
+                       copied = tty_insert_flip_char_lock(tty, ch, flag);
+                       if (copied != 1)
+                               dev_err(tup->uport.dev, "RxData PIO to tty layer failed\n");
+               }
+
        } while (1);
 
        return;
@@ -542,12 +548,11 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
        }
        dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
                                TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
-       copied = tty_insert_flip_string(tty,
+
+       copied = tty_insert_flip_string_lock(tty,
                        ((unsigned char *)(tup->rx_dma_buf_virt)), count);
-       if (copied != count) {
-               WARN_ON(1);
-               dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
-       }
+       if (copied != count)
+               dev_err(tup->uport.dev, "RxData DMA copy to tty layer failed\n");
        dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
                                TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
 }