[media] omap3isp: resizer: Protect against races when updating crop
When updating the crop rectangle during streaming, the IRQ handler will
reprogram the resizer after the current frame. A race condition
currently exists between the set selection operation and the IRQ
handler: if the set selection operation is called twice in a row and the
IRQ handler runs only during the second call, it could reprogram the
hardware with partially updated values. Use a spinlock to protect
against that.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/platform/omap3isp/ispresizer.h b/drivers/media/platform/omap3isp/ispresizer.h
index 494f5a2..5414542 100644
--- a/drivers/media/platform/omap3isp/ispresizer.h
+++ b/drivers/media/platform/omap3isp/ispresizer.h
@@ -17,6 +17,7 @@
#ifndef OMAP3_ISP_RESIZER_H
#define OMAP3_ISP_RESIZER_H
+#include <linux/spinlock.h>
#include <linux/types.h>
/*
@@ -86,6 +87,7 @@
/*
* struct isp_res_device - OMAP3 ISP resizer module
+ * @lock: Protects formats and crop rectangles between set_selection and IRQ
* @crop.request: Crop rectangle requested by the user
* @crop.active: Active crop rectangle (based on hardware requirements)
*/
@@ -106,6 +108,7 @@
enum isp_pipeline_stream_state state;
wait_queue_head_t wait;
atomic_t stopping;
+ spinlock_t lock;
struct {
struct v4l2_rect request;