[PATCH v4 18/26] media: ipu3-cio2: Release the cio2 device context by media device callback

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Use the media device release callback to release the cio2 device's data
structure. This approach has the benefit of not releasing memory which may
still be accessed through open file handles whilst the ipu3-cio2 driver is
being unbound.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/pci/intel/ipu3/ipu3-cio2.c | 72 ++++++++++++++++--------
 1 file changed, 47 insertions(+), 25 deletions(-)

diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
index 81ec8630453b..2f1202b2bc77 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
@@ -239,9 +239,15 @@ static int cio2_fbpt_init(struct cio2_device *cio2, struct cio2_queue *q)
 	return 0;
 }
 
-static void cio2_fbpt_exit(struct cio2_queue *q, struct device *dev)
+static int cio2_fbpt_exit(struct cio2_queue *q, struct device *dev)
 {
+	if (!q->fbpt)
+		return -ENOENT;
+
 	dma_free_coherent(dev, CIO2_FBPT_SIZE, q->fbpt, q->fbpt_bus_addr);
+	q->fbpt = NULL;
+
+	return 0;
 }
 
 /**************** CSI2 hardware setup ****************/
@@ -1631,13 +1637,16 @@ static int cio2_queue_init(struct cio2_device *cio2, struct cio2_queue *q)
 
 static void cio2_queue_exit(struct cio2_device *cio2, struct cio2_queue *q)
 {
-	vb2_video_unregister_device(&q->vdev);
 	media_entity_cleanup(&q->vdev.entity);
-	v4l2_device_unregister_subdev(&q->subdev);
 	media_entity_cleanup(&q->subdev.entity);
-	cio2_fbpt_exit(q, &cio2->pci_dev->dev);
-	mutex_destroy(&q->subdev_lock);
-	mutex_destroy(&q->lock);
+	/*
+	 * Note that not all mutexes may have been initialised, destroy only
+	 * those that have.
+	 */
+	if (!cio2_fbpt_exit(q, &cio2->pci_dev->dev)) {
+		mutex_destroy(&q->subdev_lock);
+		mutex_destroy(&q->lock);
+	}
 }
 
 static int cio2_queues_init(struct cio2_device *cio2)
@@ -1647,16 +1656,10 @@ static int cio2_queues_init(struct cio2_device *cio2)
 	for (i = 0; i < CIO2_QUEUES; i++) {
 		r = cio2_queue_init(cio2, &cio2->queue[i]);
 		if (r)
-			break;
+			return r;
 	}
 
-	if (i == CIO2_QUEUES)
-		return 0;
-
-	for (i--; i >= 0; i--)
-		cio2_queue_exit(cio2, &cio2->queue[i]);
-
-	return r;
+	return 0;
 }
 
 static void cio2_queues_exit(struct cio2_device *cio2)
@@ -1667,6 +1670,22 @@ static void cio2_queues_exit(struct cio2_device *cio2)
 		cio2_queue_exit(cio2, &cio2->queue[i]);
 }
 
+static void cio2_media_release(struct media_device *mdev)
+{
+	struct cio2_device *cio2 =
+		container_of(mdev, struct cio2_device, media_dev);
+
+	cio2_queues_exit(cio2);
+	cio2_fbpt_exit_dummy(cio2);
+	mutex_destroy(&cio2->lock);
+
+	kfree(cio2);
+}
+
+static const struct media_device_ops cio2_mdev_ops = {
+	.release = cio2_media_release,
+};
+
 /**************** PCI interface ****************/
 
 static int cio2_pci_probe(struct pci_dev *pci_dev,
@@ -1685,7 +1704,7 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
 	if (r)
 		return r;
 
-	cio2 = devm_kzalloc(dev, sizeof(*cio2), GFP_KERNEL);
+	cio2 = kzalloc(sizeof(*cio2), GFP_KERNEL);
 	if (!cio2)
 		return -ENOMEM;
 	cio2->pci_dev = pci_dev;
@@ -1730,6 +1749,7 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
 	mutex_init(&cio2->lock);
 
 	cio2->media_dev.dev = dev;
+	cio2->media_dev.ops = &cio2_mdev_ops;
 	strscpy(cio2->media_dev.model, CIO2_DEVICE_NAME,
 		sizeof(cio2->media_dev.model));
 	cio2->media_dev.hw_revision = 0;
@@ -1737,7 +1757,7 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
 	media_device_init(&cio2->media_dev);
 	r = media_device_register(&cio2->media_dev);
 	if (r < 0)
-		goto fail_mutex_destroy;
+		goto fail_media_device_put;
 
 	cio2->v4l2_dev.mdev = &cio2->media_dev;
 	r = v4l2_device_register(dev, &cio2->v4l2_dev);
@@ -1772,34 +1792,36 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
 fail_clean_notifier:
 	v4l2_async_nf_unregister(&cio2->notifier);
 	v4l2_async_nf_cleanup(&cio2->notifier);
-	cio2_queues_exit(cio2);
+
 fail_v4l2_device_unregister:
 	v4l2_device_unregister(&cio2->v4l2_dev);
+
 fail_media_device_unregister:
 	media_device_unregister(&cio2->media_dev);
-	media_device_cleanup(&cio2->media_dev);
-fail_mutex_destroy:
-	mutex_destroy(&cio2->lock);
-	cio2_fbpt_exit_dummy(cio2);
 
+fail_media_device_put:
+	media_device_put(&cio2->media_dev);
 	return r;
 }
 
 static void cio2_pci_remove(struct pci_dev *pci_dev)
 {
 	struct cio2_device *cio2 = pci_get_drvdata(pci_dev);
+	unsigned int i;
 
 	media_device_unregister(&cio2->media_dev);
 	v4l2_async_nf_unregister(&cio2->notifier);
 	v4l2_async_nf_cleanup(&cio2->notifier);
-	cio2_queues_exit(cio2);
-	cio2_fbpt_exit_dummy(cio2);
+	for (i = 0; i < CIO2_QUEUES; i++) {
+		vb2_video_unregister_device(&cio2->queue[i].vdev);
+		v4l2_device_unregister_subdev(&cio2->queue[i].subdev);
+	}
 	v4l2_device_unregister(&cio2->v4l2_dev);
-	media_device_cleanup(&cio2->media_dev);
-	mutex_destroy(&cio2->lock);
 
 	pm_runtime_forbid(&pci_dev->dev);
 	pm_runtime_get_noresume(&pci_dev->dev);
+
+	media_device_put(&cio2->media_dev);
 }
 
 static int __maybe_unused cio2_runtime_suspend(struct device *dev)
-- 
2.39.2