[PATCH 11/35] media: s2255: Use refcount_t instead of atomic_t for num_channels

Ricardo Ribalda
2024-04-15T19:34:40Z

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.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/usb/s2255/s2255drv.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/media/usb/s2255/s2255drv.c b/drivers/media/usb/s2255/s2255drv.c
index 8e1de1e8bd12..a6e450181fd0 100644
--- a/drivers/media/usb/s2255/s2255drv.c
+++ b/drivers/media/usb/s2255/s2255drv.c
@@ -247,7 +247,7 @@ struct s2255_vc {
struct s2255_dev {
struct s2255_vc vc[MAX_CHANNELS];
struct v4l2_device v4l2_dev;
- atomic_t num_channels;
+ refcount_t num_channels;
int frames;
struct mutex lock; /* channels[].vdev.lock */
struct mutex cmdlock; /* protects cmdbuf */
@@ -1550,11 +1550,11 @@ static void s2255_video_device_release(struct video_device *vdev)
container_of(vdev, struct s2255_vc, vdev);

dprintk(dev, 4, "%s, chnls: %d\n", __func__,
- atomic_read(&dev->num_channels));
+ refcount_read(&dev->num_channels));

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);
return;
}
@@ -1659,7 +1659,7 @@ static int s2255_probe_v4l(struct s2255_dev *dev)
"failed to register video device!\n");
break;
}
- atomic_inc(&dev->num_channels);
+ refcount_inc(&dev->num_channels);
v4l2_info(&dev->v4l2_dev, "V4L2 device registered as %s\n",
video_device_node_name(&vc->vdev));

@@ -1667,11 +1667,11 @@ static int s2255_probe_v4l(struct s2255_dev *dev)
pr_info("Sensoray 2255 V4L driver Revision: %s\n",
S2255_VERSION);
/* 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);
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");
return 0;
}
@@ -2221,7 +2221,7 @@ static int s2255_probe(struct usb_interface *interface,
goto errorFWDATA1;
}

- atomic_set(&dev->num_channels, 0);
+ refcount_set(&dev->num_channels, 0);
dev->pid = id->idProduct;
dev->fw_data = kzalloc(sizeof(struct s2255_fw), GFP_KERNEL);
if (!dev->fw_data)
@@ -2341,12 +2341,12 @@ static void s2255_disconnect(struct usb_interface *interface)
{
struct s2255_dev *dev = to_s2255_dev(usb_get_intfdata(interface));
int i;
- int channels = atomic_read(&dev->num_channels);
+ int channels = refcount_read(&dev->num_channels);
mutex_lock(&dev->lock);
v4l2_device_disconnect(&dev->v4l2_dev);
mutex_unlock(&dev->lock);
/*see comments in the uvc_driver.c usb disconnect function */
- atomic_inc(&dev->num_channels);
+ refcount_inc(&dev->num_channels);
/* unregister each video device. */
for (i = 0; i < channels; i++)
video_unregister_device(&dev->vc[i].vdev);
@@ -2359,7 +2359,7 @@ static void s2255_disconnect(struct usb_interface *interface)
dev->vc[i].vidstatus_ready = 1;
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);
dev_info(&interface->dev, "%s\n", __func__);
}

--
2.44.0.683.g7961c838ac-goog