From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
We need to serialize streamon/off with queueing new requests.
These ioctls may trigger the cancellation of a streaming
operation, and that should not be mixed with queuing a new
request at the same time.
Finally close() needs this lock since that too can trigger the
cancellation of a streaming operation.
We take the req_queue_mutex here before any other locks since
it is a very high-level lock.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-dev.c | 13 +++++++++++++
drivers/media/v4l2-core/v4l2-ioctl.c | 22 +++++++++++++++++++++-
2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 4ffd7d60a901..d23e82ab1e27 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -444,8 +444,21 @@ static int v4l2_release(struct inode *inode, struct file *filp)
struct video_device *vdev = video_devdata(filp);
int ret = 0;
+ /*
+ * We need to serialize the release() with queueing new requests.
+ * The release() may trigger the cancellation of a streaming
+ * operation, and that should not be mixed with queueing a new
+ * request at the same time.
+ */
+ if (v4l2_device_supports_requests(vdev->v4l2_dev))
+ mutex_lock(&vdev->v4l2_dev->mdev->req_queue_mutex);
+
if (vdev->fops->release)
ret = vdev->fops->release(filp);
+
+ if (v4l2_device_supports_requests(vdev->v4l2_dev))
+ mutex_unlock(&vdev->v4l2_dev->mdev->req_queue_mutex);
+
if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
dprintk("%s: release\n",
video_device_node_name(vdev));
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 965fd301f617..27a893aa0664 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2714,6 +2714,7 @@ static long __video_do_ioctl(struct file *file,
unsigned int cmd, void *arg)
{
struct video_device *vfd = video_devdata(file);
+ struct mutex *req_queue_lock = NULL;
struct mutex *lock; /* ioctl serialization mutex */
const struct v4l2_ioctl_ops *ops = vfd->ioctl_ops;
bool write_only = false;
@@ -2733,10 +2734,27 @@ static long __video_do_ioctl(struct file *file,
if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags))
vfh = file->private_data;
+ /*
+ * We need to serialize streamon/off with queueing new requests.
+ * These ioctls may trigger the cancellation of a streaming
+ * operation, and that should not be mixed with queueing a new
+ * request at the same time.
+ */
+ if (v4l2_device_supports_requests(vfd->v4l2_dev) &&
+ (cmd == VIDIOC_STREAMON || cmd == VIDIOC_STREAMOFF)) {
+ req_queue_lock = &vfd->v4l2_dev->mdev->req_queue_mutex;
+
+ if (req_queue_lock && mutex_lock_interruptible(req_queue_lock))
+ return -ERESTARTSYS;
+ }
+
lock = v4l2_ioctl_get_lock(vfd, cmd);
- if (lock && mutex_lock_interruptible(lock))
+ if (lock && mutex_lock_interruptible(lock)) {
+ if (req_queue_lock)
+ mutex_unlock(req_queue_lock);
return -ERESTARTSYS;
+ }
if (!video_is_registered(vfd)) {
ret = -ENODEV;
@@ -2795,6 +2813,8 @@ static long __video_do_ioctl(struct file *file,
unlock:
if (lock)
mutex_unlock(lock);
+ if (req_queue_lock)
+ mutex_unlock(req_queue_lock);
return ret;
}
--
2.17.0
