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/dw_spi.c b/drivers/spi/dw_spi.c
index 9a6196461b27..d040debc07c2 100644
--- a/drivers/spi/dw_spi.c
+++ b/drivers/spi/dw_spi.c
@@ -821,7 +821,7 @@ static int stop_queue(struct dw_spi *dws)
 
         spin_lock_irqsave(&dws->lock, flags);
         dws->run = QUEUE_STOPPED;
-        while (!list_empty(&dws->queue) && dws->busy && limit--) {
+        while ((!list_empty(&dws->queue) || dws->busy) && limit--) {
                 spin_unlock_irqrestore(&dws->lock, flags);
                 msleep(10);
                 spin_lock_irqsave(&dws->lock, flags);