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Commit 850a28ec authored by Vasily Khoruzhick's avatar Vasily Khoruzhick Committed by Grant Likely
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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: default avatarVasily Khoruzhick <anarsoul@gmail.com>
Acked-by: default avatarEric Miao <eric.y.miao@gmail.com>
Acked-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 454abcc5

drivers/spi/amba-pl022.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/spi/dw_spi.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/spi/pxa2xx_spi.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/spi/spi_bfin5xx.c

+1 −1
Original line number Diff line number Diff line
@@ -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);