From b6951b8a63e8764558c066369a6317bfe15dca55 Mon Sep 17 00:00:00 2001 From: Bin Gao Date: Wed, 9 Oct 2013 10:39:17 +0800 Subject: [PATCH] serial: mrst_max3110: Fix race condition between spi transfers There is a race between termios configuration and xmit that can cause the intel_mid_ssp_spi driver to stall. Serializing spi transactions fixes the problem. Signed-off-by: Bin Gao Signed-off-by: Feng Tang Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/mrst_max3110.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/mrst_max3110.c b/drivers/tty/serial/mrst_max3110.c index ee77e7366ed6..565779dc7aac 100644 --- a/drivers/tty/serial/mrst_max3110.c +++ b/drivers/tty/serial/mrst_max3110.c @@ -61,6 +61,7 @@ struct uart_max3110 { struct task_struct *main_thread; struct task_struct *read_thread; struct mutex thread_mutex; + struct mutex io_mutex; u32 baud; u16 cur_conf; @@ -90,6 +91,7 @@ static int max3110_write_then_read(struct uart_max3110 *max, struct spi_transfer x; int ret; + mutex_lock(&max->io_mutex); spi_message_init(&message); memset(&x, 0, sizeof x); x.len = len; @@ -104,6 +106,7 @@ static int max3110_write_then_read(struct uart_max3110 *max, /* Do the i/o */ ret = spi_sync(spi, &message); + mutex_unlock(&max->io_mutex); return ret; } @@ -805,6 +808,7 @@ static int serial_m3110_probe(struct spi_device *spi) max->irq = (u16)spi->irq; mutex_init(&max->thread_mutex); + mutex_init(&max->io_mutex); max->word_7bits = 0; max->parity = 0; -- 2.11.0