spi: Fix race condition in stop_queue()

There's a race condition in stop_queue() in some drivers -
if drv_data->queue is empty, but drv_data->busy is still set
(or opposite situation) stop_queue will return -EBUSY.
So fix loop condition to check that both drv_data->queue is empty
and drv_data->busy is not set.

This patch affects following drivers:
pxa2xx_spi
spi_bfin5xx
amba-pl022
dw_spi

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index a429b01d0285..3aa782067b68 100644
--- a/drivers/spi/pxa2xx_spi.c
+++ b/drivers/spi/pxa2xx_spi.c
@@ -1493,7 +1493,7 @@ static int stop_queue(struct driver_data *drv_data)
          * execution path (pump_messages) would be required to call wake_up or
          * friends on every SPI message. Do this instead */
         drv_data->run = QUEUE_STOPPED;
-        while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) {
+        while ((!list_empty(&drv_data->queue) || drv_data->busy) && limit--) {
                 spin_unlock_irqrestore(&drv_data->lock, flags);
                 msleep(10);
                 spin_lock_irqsave(&drv_data->lock, flags);