[PATCH 0/4] media: drop redundant device references

[PATCH 0/4] media: drop redundant device references

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop redundant device references to reduce cargo culting, make it easier
to spot drivers where extra references are needed, and reduce the risk
of memory leaks when drivers fail to release them.

Johan


Johan Hovold (4):
  media: imon: drop redundant device references
  media: mceusb: drop redundant device reference
  media: go7007-loader: drop redundant device reference
  media: usbtv: drop redundant device reference

 drivers/media/rc/imon.c                  | 13 +++----------
 drivers/media/rc/mceusb.c                |  4 +---
 drivers/media/usb/go7007/go7007-loader.c |  6 +-----
 drivers/media/usb/usbtv/usbtv-core.c     |  4 +---
 4 files changed, 6 insertions(+), 21 deletions(-)

-- 
2.52.0

[PATCH 1/4] media: imon: drop redundant device references

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop the redundant device references to reduce cargo culting, make it
easier to spot drivers where extra references are needed, and reduce the
risk of memory leaks when drivers fail to release them.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/rc/imon.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 7e92161105d5..ecea0085d411 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -2250,7 +2250,7 @@ static struct imon_context *imon_init_intf0(struct usb_interface *intf,
 	mutex_lock(&ictx->lock);
 
 	ictx->dev = dev;
-	ictx->usbdev_intf0 = usb_get_dev(interface_to_usbdev(intf));
+	ictx->usbdev_intf0 = interface_to_usbdev(intf);
 	ictx->rx_urb_intf0 = rx_urb;
 	ictx->tx_urb = tx_urb;
 	ictx->rf_device = false;
@@ -2308,7 +2308,6 @@ static struct imon_context *imon_init_intf0(struct usb_interface *intf,
 	usb_kill_urb(ictx->rx_urb_intf0);
 urb_submit_failed:
 find_endpoint_failed:
-	usb_put_dev(ictx->usbdev_intf0);
 	mutex_unlock(&ictx->lock);
 	usb_free_urb(tx_urb);
 tx_urb_alloc_failed:
@@ -2338,7 +2337,7 @@ static struct imon_context *imon_init_intf1(struct usb_interface *intf,
 		timer_setup(&ictx->ttimer, imon_touch_display_timeout, 0);
 	}
 
-	ictx->usbdev_intf1 = usb_get_dev(interface_to_usbdev(intf));
+	ictx->usbdev_intf1 = interface_to_usbdev(intf);
 	ictx->rx_urb_intf1 = rx_urb;
 
 	ret = -ENODEV;
@@ -2377,7 +2376,6 @@ static struct imon_context *imon_init_intf1(struct usb_interface *intf,
 		input_unregister_device(ictx->touch);
 touch_setup_failed:
 find_endpoint_failed:
-	usb_put_dev(ictx->usbdev_intf1);
 	ictx->usbdev_intf1 = NULL;
 	mutex_unlock(&ictx->lock);
 	usb_free_urb(rx_urb);
@@ -2426,7 +2424,7 @@ static int imon_probe(struct usb_interface *interface,
 	struct imon_context *ictx = NULL;
 	u16 vendor, product;
 
-	usbdev     = usb_get_dev(interface_to_usbdev(interface));
+	usbdev     = interface_to_usbdev(interface);
 	iface_desc = interface->cur_altsetting;
 	ifnum      = iface_desc->desc.bInterfaceNumber;
 	vendor     = le16_to_cpu(usbdev->descriptor.idVendor);
@@ -2495,12 +2493,9 @@ static int imon_probe(struct usb_interface *interface,
 		 vendor, product, ifnum,
 		 usbdev->bus->busnum, usbdev->devnum);
 
-	usb_put_dev(usbdev);
-
 	return 0;
 
 fail:
-	usb_put_dev(usbdev);
 	dev_err(dev, "unable to register, err %d\n", ret);
 
 	return ret;
@@ -2550,7 +2545,6 @@ static void imon_disconnect(struct usb_interface *interface)
 			else if (ictx->display_type == IMON_DISPLAY_TYPE_VFD)
 				usb_deregister_dev(interface, &imon_vfd_class);
 		}
-		usb_put_dev(ictx->usbdev_intf0);
 	} else {
 		ictx->dev_present_intf1 = false;
 		usb_kill_urb(ictx->rx_urb_intf1);
@@ -2558,7 +2552,6 @@ static void imon_disconnect(struct usb_interface *interface)
 			timer_delete_sync(&ictx->ttimer);
 			input_unregister_device(ictx->touch);
 		}
-		usb_put_dev(ictx->usbdev_intf1);
 	}
 
 	if (refcount_dec_and_test(&ictx->users))
-- 
2.52.0

[PATCH 2/4] media: mceusb: drop redundant device reference

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop the redundant device reference to reduce cargo culting, make it
easier to spot drivers where an extra reference is needed, and reduce
the risk of memory leaks when drivers fail to release it.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/rc/mceusb.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/media/rc/mceusb.c b/drivers/media/rc/mceusb.c
index ed55e9ec3c57..d9bdf0b9487a 100644
--- a/drivers/media/rc/mceusb.c
+++ b/drivers/media/rc/mceusb.c
@@ -1729,7 +1729,7 @@ static int mceusb_dev_probe(struct usb_interface *intf,
 		goto urb_in_alloc_fail;
 
 	ir->usbintf = intf;
-	ir->usbdev = usb_get_dev(dev);
+	ir->usbdev = dev;
 	ir->dev = &intf->dev;
 	ir->len_in = maxp;
 	ir->flags.microsoft_gen1 = is_microsoft_gen1;
@@ -1817,7 +1817,6 @@ static int mceusb_dev_probe(struct usb_interface *intf,
 	/* Error-handling path */
 rc_dev_fail:
 	cancel_work_sync(&ir->kevent);
-	usb_put_dev(ir->usbdev);
 	usb_kill_urb(ir->urb_in);
 	usb_free_urb(ir->urb_in);
 urb_in_alloc_fail:
@@ -1849,7 +1848,6 @@ static void mceusb_dev_disconnect(struct usb_interface *intf)
 	usb_kill_urb(ir->urb_in);
 	usb_free_urb(ir->urb_in);
 	usb_free_coherent(dev, ir->len_in, ir->buf_in, ir->dma_in);
-	usb_put_dev(dev);
 
 	kfree(ir);
 }
-- 
2.52.0

[PATCH 3/4] media: go7007-loader: drop redundant device reference

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop the redundant device reference to reduce cargo culting, make it
easier to spot drivers where an extra reference is needed, and reduce
the risk of memory leaks when drivers fail to release it.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/usb/go7007/go7007-loader.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/media/usb/go7007/go7007-loader.c b/drivers/media/usb/go7007/go7007-loader.c
index 243aa0ad074c..5747e6e4f2d6 100644
--- a/drivers/media/usb/go7007/go7007-loader.c
+++ b/drivers/media/usb/go7007/go7007-loader.c
@@ -41,9 +41,7 @@ static int go7007_loader_probe(struct usb_interface *interface,
 	int ret;
 	int i;
 
-	usbdev = usb_get_dev(interface_to_usbdev(interface));
-	if (!usbdev)
-		goto failed2;
+	usbdev = interface_to_usbdev(interface);
 
 	if (usbdev->descriptor.bNumConfigurations != 1) {
 		dev_err(&interface->dev, "can't handle multiple config\n");
@@ -96,7 +94,6 @@ static int go7007_loader_probe(struct usb_interface *interface,
 	return 0;
 
 failed2:
-	usb_put_dev(usbdev);
 	dev_err(&interface->dev, "probe failed\n");
 	return -ENODEV;
 }
@@ -104,7 +101,6 @@ static int go7007_loader_probe(struct usb_interface *interface,
 static void go7007_loader_disconnect(struct usb_interface *interface)
 {
 	dev_info(&interface->dev, "disconnect\n");
-	usb_put_dev(interface_to_usbdev(interface));
 	usb_set_intfdata(interface, NULL);
 }
 
-- 
2.52.0

[PATCH 4/4] media: usbtv: drop redundant device reference

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop the redundant device reference to reduce cargo culting, make it
easier to spot drivers where an extra reference is needed, and reduce
the risk of memory leaks when drivers fail to release it.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/usb/usbtv/usbtv-core.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/media/usb/usbtv/usbtv-core.c b/drivers/media/usb/usbtv/usbtv-core.c
index c4bfadbe63c9..6c4facf4f41a 100644
--- a/drivers/media/usb/usbtv/usbtv-core.c
+++ b/drivers/media/usb/usbtv/usbtv-core.c
@@ -91,7 +91,7 @@ static int usbtv_probe(struct usb_interface *intf,
 	if (usbtv == NULL)
 		return -ENOMEM;
 	usbtv->dev = dev;
-	usbtv->udev = usb_get_dev(interface_to_usbdev(intf));
+	usbtv->udev = interface_to_usbdev(intf);
 
 	usbtv->iso_size = size;
 
@@ -119,7 +119,6 @@ static int usbtv_probe(struct usb_interface *intf,
 
 usbtv_video_fail:
 	usb_set_intfdata(intf, NULL);
-	usb_put_dev(usbtv->udev);
 	kfree(usbtv);
 
 	return ret;
@@ -137,7 +136,6 @@ static void usbtv_disconnect(struct usb_interface *intf)
 	usbtv_audio_free(usbtv);
 	usbtv_video_free(usbtv);
 
-	usb_put_dev(usbtv->udev);
 	usbtv->udev = NULL;
 
 	/* the usbtv structure will be deallocated when v4l2 will be
-- 
2.52.0