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/amba-pl022.c b/drivers/spi/amba-pl022.c
index 5a4e0afb9ad6..4b8357b728cb 100644
--- a/drivers/spi/amba-pl022.c
+++ b/drivers/spi/amba-pl022.c
@@ -1555,7 +1555,7 @@ static int stop_queue(struct pl022 *pl022)
          * A wait_queue on the pl022->busy could be used, but then the common
          * execution path (pump_messages) would be required to call wake_up or
          * friends on every SPI message. Do this instead */
-        while (!list_empty(&pl022->queue) && pl022->busy && limit--) {
+        while ((!list_empty(&pl022->queue) || pl022->busy) && limit--) {
                 spin_unlock_irqrestore(&pl022->queue_lock, flags);
                 msleep(10);
                 spin_lock_irqsave(&pl022->queue_lock, flags);