V4L/DVB (7501): soc-camera: use a spinlock for videobuffer queue

All drivers should provide a spinlock to be used in videobuf operations.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Reviewed-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/pxa_camera.c

@@ -803,6 +803,15 @@ static int pxa_camera_querycap(struct soc_camera_host *ici,
 	return 0;
 }
 
+static spinlock_t *pxa_camera_spinlock_alloc(struct soc_camera_file *icf)
+{
+	struct soc_camera_host *ici =
+		to_soc_camera_host(icf->icd->dev.parent);
+	struct pxa_camera_dev *pcdev = ici->priv;
+
+	return &pcdev->lock;
+}
+
 static struct soc_camera_host_ops pxa_soc_camera_host_ops = {
 	.owner		= THIS_MODULE,
 	.add		= pxa_camera_add_device,
@@ -814,6 +823,7 @@ static struct soc_camera_host_ops pxa_soc_camera_host_ops = {
 	.querycap	= pxa_camera_querycap,
 	.try_bus_param	= pxa_camera_try_bus_param,
 	.set_bus_param	= pxa_camera_set_bus_param,
+	.spinlock_alloc	= pxa_camera_spinlock_alloc,
 };
 
 /* Should be allocated dynamically too, but we have only one. */

drivers/media/video/soc_camera.c

@@ -184,6 +184,7 @@ static int soc_camera_open(struct inode *inode, struct file *file)
 	struct soc_camera_device *icd;
 	struct soc_camera_host *ici;
 	struct soc_camera_file *icf;
+	spinlock_t *lock;
 	int ret;
 
 	icf = vmalloc(sizeof(*icf));
@@ -209,10 +210,16 @@ static int soc_camera_open(struct inode *inode, struct file *file)
 		goto emgi;
 	}
 
-	icd->use_count++;
-
 	icf->icd = icd;
 
+	icf->lock = ici->ops->spinlock_alloc(icf);
+	if (!icf->lock) {
+		ret = -ENOMEM;
+		goto esla;
+	}
+
+	icd->use_count++;
+
 	/* Now we really have to activate the camera */
 	if (icd->use_count == 1) {
 		ret = ici->ops->add(icd);
@@ -229,8 +236,8 @@ static int soc_camera_open(struct inode *inode, struct file *file)
 	dev_dbg(&icd->dev, "camera device open\n");
 
 	/* We must pass NULL as dev pointer, then all pci_* dma operations
-	 * transform to normal dma_* ones. Do we need an irqlock? */
-	videobuf_queue_sg_init(&icf->vb_vidq, ici->vbq_ops, NULL, NULL,
+	 * transform to normal dma_* ones. */
+	videobuf_queue_sg_init(&icf->vb_vidq, ici->vbq_ops, NULL, icf->lock,
 				V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_NONE,
 				ici->msize, icd);
 
@@ -238,6 +245,11 @@ static int soc_camera_open(struct inode *inode, struct file *file)
 
 	/* All errors are entered with the video_lock held */
 eiciadd:
+	lock = icf->lock;
+	icf->lock = NULL;
+	if (ici->ops->spinlock_free)
+		ici->ops->spinlock_free(lock);
+esla:
 	module_put(ici->ops->owner);
 emgi:
 	module_put(icd->ops->owner);
@@ -253,16 +265,20 @@ static int soc_camera_close(struct inode *inode, struct file *file)
 	struct soc_camera_device *icd = icf->icd;
 	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
 	struct video_device *vdev = icd->vdev;
+	spinlock_t *lock = icf->lock;
 
 	mutex_lock(&video_lock);
 	icd->use_count--;
 	if (!icd->use_count)
 		ici->ops->remove(icd);
+	icf->lock = NULL;
+	if (ici->ops->spinlock_free)
+		ici->ops->spinlock_free(lock);
 	module_put(icd->ops->owner);
 	module_put(ici->ops->owner);
 	mutex_unlock(&video_lock);
 
-	vfree(file->private_data);
+	vfree(icf);
 
 	dev_dbg(vdev->dev, "camera device close\n");
 
@@ -762,6 +778,21 @@ static void dummy_release(struct device *dev)
 {
 }
 
+static spinlock_t *spinlock_alloc(struct soc_camera_file *icf)
+{
+	spinlock_t *lock = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
+
+	if (lock)
+		spin_lock_init(lock);
+
+	return lock;
+}
+
+static void spinlock_free(spinlock_t *lock)
+{
+	kfree(lock);
+}
+
 int soc_camera_host_register(struct soc_camera_host *ici)
 {
 	int ret;
@@ -792,6 +823,11 @@ int soc_camera_host_register(struct soc_camera_host *ici)
 	if (ret)
 		goto edevr;
 
+	if (!ici->ops->spinlock_alloc) {
+		ici->ops->spinlock_alloc = spinlock_alloc;
+		ici->ops->spinlock_free = spinlock_free;
+	}
+
 	scan_add_host(ici);
 
 	return 0;

include/media/soc_camera.h

@@ -48,6 +48,7 @@ struct soc_camera_device {
 struct soc_camera_file {
 	struct soc_camera_device *icd;
 	struct videobuf_queue vb_vidq;
+	spinlock_t *lock;
 };
 
 struct soc_camera_host {
@@ -73,6 +74,8 @@ struct soc_camera_host_ops {
 	int (*try_bus_param)(struct soc_camera_device *, __u32);
 	int (*set_bus_param)(struct soc_camera_device *, __u32);
 	unsigned int (*poll)(struct file *, poll_table *);
+	spinlock_t* (*spinlock_alloc)(struct soc_camera_file *);
+	void (*spinlock_free)(spinlock_t *);
 };
 
 struct soc_camera_link {