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 <[email protected]>
Acked-by: Eric Miao <[email protected]>
Acked-by: Mike Frysinger <[email protected]>
Signed-off-by: Grant Likely <[email protected]>

diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c
index 5a4e0afb9ad6dc39e8a3bb041c72d0b8f21e60f7..4b8357b728cb14c6bcd08452b445c854f2d18db1 100644 (file)
--- 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);

diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c
index 9a6196461b27a0318fc52a8150eb0ee5161fac0c..d040debc07c2fa3b5790d5ceb18b309ba039635c 100644 (file)
--- 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);

diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index a429b01d0285edba75055df0dd49b6a5184ec68f..3aa782067b68adcacd44cec3f23d46b8c8f8e2a1 100644 (file)
--- 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);

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index a28462486df8c6f53eabd609a01e18cc8d361314..f3a1c52c0fb054cdeeac4b0697c53a598a29c9ac 100644 (file)
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -1284,7 +1284,7 @@ static inline int bfin_spi_stop_queue(struct bfin_spi_master_data *drv_data)
         * friends on every SPI message. Do this instead
         */
        drv_data->running = false;
-       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);