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Commit 32f2f538 authored by Ricardo Ribalda's avatar Ricardo Ribalda Committed by Greg Kroah-Hartman
Browse files

media: s2255: Use refcount_t instead of atomic_t for num_channels 

[ Upstream commit 6cff72f6bcee89228a662435b7c47e21a391c8d0 ]

Use an API that resembles more the actual use of num_channels.

Found by cocci:
drivers/media/usb/s2255/s2255drv.c:2362:5-24: WARNING: atomic_dec_and_test variation before object free at line 2363.
drivers/media/usb/s2255/s2255drv.c:1557:5-24: WARNING: atomic_dec_and_test variation before object free at line 1558.

Link: https://lore.kernel.org/linux-media/20240429-fix-cocci-v3-11-3c4865f5a4b0@chromium.org


Signed-off-by: default avatarRicardo Ribalda <ribalda@chromium.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 2401cbc0

drivers/media/usb/s2255/s2255drv.c

+10 −10
Original line number Original line Diff line number Diff line
@@ -256,7 +256,7 @@ struct s2255_vc { 
struct s2255_dev {

struct s2255_dev {

	struct s2255_vc         vc[MAX_CHANNELS];

	struct s2255_vc         vc[MAX_CHANNELS];

	struct v4l2_device      v4l2_dev;

	struct v4l2_device      v4l2_dev;

	atomic_t                num_channels;

	refcount_t		num_channels;

	int			frames;

	int			frames;

	struct mutex		lock;	/* channels[].vdev.lock */

	struct mutex		lock;	/* channels[].vdev.lock */

	struct mutex		cmdlock; /* protects cmdbuf */

	struct mutex		cmdlock; /* protects cmdbuf */
@@ -1574,11 +1574,11 @@ static void s2255_video_device_release(struct video_device *vdev) 
		container_of(vdev, struct s2255_vc, vdev);

		container_of(vdev, struct s2255_vc, vdev);





	dprintk(dev, 4, "%s, chnls: %d\n", __func__,

	dprintk(dev, 4, "%s, chnls: %d\n", __func__,

		atomic_read(&dev->num_channels));

		refcount_read(&dev->num_channels));





	v4l2_ctrl_handler_free(&vc->hdl);

	v4l2_ctrl_handler_free(&vc->hdl);





	if (atomic_dec_and_test(&dev->num_channels))

	if (refcount_dec_and_test(&dev->num_channels))

		s2255_destroy(dev);

		s2255_destroy(dev);

	return;

	return;

}

}
@@ -1681,7 +1681,7 @@ static int s2255_probe_v4l(struct s2255_dev *dev) 
				"failed to register video device!\n");

				"failed to register video device!\n");

			break;

			break;

		}

		}

		atomic_inc(&dev->num_channels);

		refcount_inc(&dev->num_channels);

		v4l2_info(&dev->v4l2_dev, "V4L2 device registered as %s\n",

		v4l2_info(&dev->v4l2_dev, "V4L2 device registered as %s\n",

			  video_device_node_name(&vc->vdev));

			  video_device_node_name(&vc->vdev));
@@ -1689,11 +1689,11 @@ static int s2255_probe_v4l(struct s2255_dev *dev) 
	pr_info("Sensoray 2255 V4L driver Revision: %s\n",

	pr_info("Sensoray 2255 V4L driver Revision: %s\n",

		S2255_VERSION);

		S2255_VERSION);

	/* if no channels registered, return error and probe will fail*/

	/* if no channels registered, return error and probe will fail*/

	if (atomic_read(&dev->num_channels) == 0) {

	if (refcount_read(&dev->num_channels) == 0) {

		v4l2_device_unregister(&dev->v4l2_dev);

		v4l2_device_unregister(&dev->v4l2_dev);

		return ret;

		return ret;

	}

	}

	if (atomic_read(&dev->num_channels) != MAX_CHANNELS)

	if (refcount_read(&dev->num_channels) != MAX_CHANNELS)

		pr_warn("s2255: Not all channels available.\n");

		pr_warn("s2255: Not all channels available.\n");

	return 0;

	return 0;

}

}
@@ -2242,7 +2242,7 @@ static int s2255_probe(struct usb_interface *interface, 
		goto errorFWDATA1;

		goto errorFWDATA1;

	}

	}





	atomic_set(&dev->num_channels, 0);

	refcount_set(&dev->num_channels, 0);

	dev->pid = id->idProduct;

	dev->pid = id->idProduct;

	dev->fw_data = kzalloc(sizeof(struct s2255_fw), GFP_KERNEL);

	dev->fw_data = kzalloc(sizeof(struct s2255_fw), GFP_KERNEL);

	if (!dev->fw_data)

	if (!dev->fw_data)
@@ -2362,12 +2362,12 @@ static void s2255_disconnect(struct usb_interface *interface) 
{

{

	struct s2255_dev *dev = to_s2255_dev(usb_get_intfdata(interface));

	struct s2255_dev *dev = to_s2255_dev(usb_get_intfdata(interface));

	int i;

	int i;

	int channels = atomic_read(&dev->num_channels);

	int channels = refcount_read(&dev->num_channels);

	mutex_lock(&dev->lock);

	mutex_lock(&dev->lock);

	v4l2_device_disconnect(&dev->v4l2_dev);

	v4l2_device_disconnect(&dev->v4l2_dev);

	mutex_unlock(&dev->lock);

	mutex_unlock(&dev->lock);

	/*see comments in the uvc_driver.c usb disconnect function */

	/*see comments in the uvc_driver.c usb disconnect function */

	atomic_inc(&dev->num_channels);

	refcount_inc(&dev->num_channels);

	/* unregister each video device. */

	/* unregister each video device. */

	for (i = 0; i < channels; i++)

	for (i = 0; i < channels; i++)

		video_unregister_device(&dev->vc[i].vdev);

		video_unregister_device(&dev->vc[i].vdev);
@@ -2380,7 +2380,7 @@ static void s2255_disconnect(struct usb_interface *interface) 
		dev->vc[i].vidstatus_ready = 1;

		dev->vc[i].vidstatus_ready = 1;

		wake_up(&dev->vc[i].wait_vidstatus);

		wake_up(&dev->vc[i].wait_vidstatus);

	}

	}

	if (atomic_dec_and_test(&dev->num_channels))

	if (refcount_dec_and_test(&dev->num_channels))

		s2255_destroy(dev);

		s2255_destroy(dev);

	dev_info(&interface->dev, "%s\n", __func__);

	dev_info(&interface->dev, "%s\n", __func__);

}

}