From: Hans Verkuil <hans.verk...@cisco.com>
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.
Also TRY/S_EXT_CTRLS needs this lock to correctly serialize
with MEDIA_REQUEST_IOC_QUEUE.
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.verk...@cisco.com>
---
drivers/media/v4l2-core/v4l2-dev.c | 37 +++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/drivers/media/v4l2-core/v4l2-dev.c
b/drivers/media/v4l2-core/v4l2-dev.c
index 1d0b2208e8fb..b1c9efc0ecc4 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -353,13 +353,36 @@ static long v4l2_ioctl(struct file *filp, unsigned int
cmd, unsigned long arg)
if (vdev->fops->unlocked_ioctl) {
struct mutex *lock = v4l2_ioctl_get_lock(vdev, cmd);
+ struct mutex *queue_lock = NULL;
- if (lock && mutex_lock_interruptible(lock))
+ /*
+ * 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.
+ *
+ * Also TRY/S_EXT_CTRLS needs this lock to correctly serialize
+ * with MEDIA_REQUEST_IOC_QUEUE.
+ */
+ if (vdev->v4l2_dev->mdev &&
+ (cmd == VIDIOC_STREAMON || cmd == VIDIOC_STREAMOFF ||
+ cmd == VIDIOC_S_EXT_CTRLS || cmd == VIDIOC_TRY_EXT_CTRLS))
+ queue_lock = &vdev->v4l2_dev->mdev->req_queue_mutex;
+
+ if (queue_lock && mutex_lock_interruptible(queue_lock))
+ return -ERESTARTSYS;
+
+ if (lock && mutex_lock_interruptible(lock)) {
+ if (queue_lock)
+ mutex_unlock(queue_lock);
return -ERESTARTSYS;
+ }
if (video_is_registered(vdev))
ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
if (lock)
mutex_unlock(lock);
+ if (queue_lock)
+ mutex_unlock(queue_lock);
} else
ret = -ENOTTY;
@@ -442,8 +465,20 @@ 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 (vdev->v4l2_dev->mdev)
+ mutex_lock(&vdev->v4l2_dev->mdev->req_queue_mutex);
+
if (vdev->fops->release)
ret = vdev->fops->release(filp);
+
+ if (vdev->v4l2_dev->mdev)
+ mutex_unlock(&vdev->v4l2_dev->mdev->req_queue_mutex);
if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
printk(KERN_DEBUG "%s: release\n",
video_device_node_name(vdev));
--
2.17.0
