[RFC PATCH 10/26] fsl-viu: remove V4L2_FL_LOCK_ALL_FOPS

[Hans Verkuil <hverkuil@xxxxxxxxx>]

From: Hans Verkuil <hans.verkuil@xxxxxxxxx>

Add proper locking to the file operations, allowing for the removal
of the V4L2_FL_LOCK_ALL_FOPS flag.

Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
 drivers/media/video/fsl-viu.c |   27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/media/video/fsl-viu.c b/drivers/media/video/fsl-viu.c
index 777486f..20f9810 100644
--- a/drivers/media/video/fsl-viu.c
+++ b/drivers/media/video/fsl-viu.c
@@ -1279,10 +1279,16 @@ static int viu_open(struct file *file)
 	dprintk(1, "open minor=%d type=%s users=%d\n", minor,
 		v4l2_type_names[V4L2_BUF_TYPE_VIDEO_CAPTURE], dev->users);
 
+	if (mutex_lock_interruptible(&dev->lock)) {
+		dev->users--;
+		return -ERESTARTSYS;
+	}
+
 	/* allocate and initialize per filehandle data */
 	fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 	if (!fh) {
 		dev->users--;
+		mutex_unlock(&dev->lock);
 		return -ENOMEM;
 	}
 
@@ -1325,6 +1331,7 @@ static int viu_open(struct file *file)
 				       fh->type, V4L2_FIELD_INTERLACED,
 				       sizeof(struct viu_buf), fh,
 				       &fh->dev->lock);
+	mutex_unlock(&dev->lock);
 	return 0;
 }
 
@@ -1340,9 +1347,12 @@ static ssize_t viu_read(struct file *file, char __user *data, size_t count,
 		dev->ovenable = 0;
 
 	if (fh->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
+		if (mutex_lock_interruptible(&dev->lock))
+			return -ERESTARTSYS;
 		viu_start_dma(dev);
 		ret = videobuf_read_stream(&fh->vb_vidq, data, count,
 				ppos, 0, file->f_flags & O_NONBLOCK);
+		mutex_unlock(&dev->lock);
 		return ret;
 	}
 	return 0;
@@ -1352,11 +1362,16 @@ static unsigned int viu_poll(struct file *file, struct poll_table_struct *wait)
 {
 	struct viu_fh *fh = file->private_data;
 	struct videobuf_queue *q = &fh->vb_vidq;
+	struct viu_dev *dev = fh->dev;
+	unsigned int res;
 
 	if (V4L2_BUF_TYPE_VIDEO_CAPTURE != fh->type)
 		return POLLERR;
 
-	return videobuf_poll_stream(file, q, wait);
+	mutex_lock(&dev->lock);
+	res = videobuf_poll_stream(file, q, wait);
+	mutex_unlock(&dev->lock);
+	return res;
 }
 
 static int viu_release(struct file *file)
@@ -1365,9 +1380,11 @@ static int viu_release(struct file *file)
 	struct viu_dev *dev = fh->dev;
 	int minor = video_devdata(file)->minor;
 
+	mutex_lock(&dev->lock);
 	viu_stop_dma(dev);
 	videobuf_stop(&fh->vb_vidq);
 	videobuf_mmap_free(&fh->vb_vidq);
+	mutex_unlock(&dev->lock);
 
 	kfree(fh);
 
@@ -1394,11 +1411,15 @@ void viu_reset(struct viu_reg *reg)
 static int viu_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct viu_fh *fh = file->private_data;
+	struct viu_dev *dev = fh->dev;
 	int ret;
 
 	dprintk(1, "mmap called, vma=0x%08lx\n", (unsigned long)vma);
 
+	if (mutex_lock_interruptible(&dev->lock))
+		return -ERESTARTSYS;
 	ret = videobuf_mmap_mapper(&fh->vb_vidq, vma);
+	mutex_unlock(&dev->lock);
 
 	dprintk(1, "vma start=0x%08lx, size=%ld, ret=%d\n",
 		(unsigned long)vma->vm_start,
@@ -1544,10 +1565,6 @@ static int __devinit viu_of_probe(struct platform_device *op)
 
 	/* initialize locks */
 	mutex_init(&viu_dev->lock);
-	/* Locking in file operations other than ioctl should be done
-	   by the driver, not the V4L2 core.
-	   This driver needs auditing so that this flag can be removed. */
-	set_bit(V4L2_FL_LOCK_ALL_FOPS, &viu_dev->vdev->flags);
 	viu_dev->vdev->lock = &viu_dev->lock;
 	spin_lock_init(&viu_dev->slock);
 
-- 
1.7.10

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