[PATCH 0/2] gpib: drop redundant device reference

[PATCH 0/2] gpib: 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.

Johan


Johan Hovold (2):
  gpib: agilent_82357a: drop redundant device reference
  gpib: ni_usb: drop redundant device reference

 drivers/gpib/agilent_82357a/agilent_82357a.c | 5 +----
 drivers/gpib/ni_usb/ni_usb_gpib.c            | 4 ----
 2 files changed, 1 insertion(+), 8 deletions(-)

-- 
2.52.0

[PATCH 1/2] gpib: agilent_82357a: 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/gpib/agilent_82357a/agilent_82357a.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpib/agilent_82357a/agilent_82357a.c b/drivers/gpib/agilent_82357a/agilent_82357a.c
index e1349afbf933..770ba6eb40d1 100644
--- a/drivers/gpib/agilent_82357a/agilent_82357a.c
+++ b/drivers/gpib/agilent_82357a/agilent_82357a.c
@@ -1479,7 +1479,7 @@ static int agilent_82357a_driver_probe(struct usb_interface *interface,
 
 	if (mutex_lock_interruptible(&agilent_82357a_hotplug_lock))
 		return -ERESTARTSYS;
-	usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	usb_dev = interface_to_usbdev(interface);
 	for (i = 0; i < MAX_NUM_82357A_INTERFACES; ++i) {
 		if (!agilent_82357a_driver_interfaces[i]) {
 			agilent_82357a_driver_interfaces[i] = interface;
@@ -1490,14 +1490,12 @@ static int agilent_82357a_driver_probe(struct usb_interface *interface,
 		}
 	}
 	if (i == MAX_NUM_82357A_INTERFACES) {
-		usb_put_dev(usb_dev);
 		mutex_unlock(&agilent_82357a_hotplug_lock);
 		dev_err(&usb_dev->dev, "out of space in agilent_82357a_driver_interfaces[]\n");
 		return -1;
 	}
 	path = kmalloc(path_length, GFP_KERNEL);
 	if (!path) {
-		usb_put_dev(usb_dev);
 		mutex_unlock(&agilent_82357a_hotplug_lock);
 		return -ENOMEM;
 	}
@@ -1539,7 +1537,6 @@ static void agilent_82357a_driver_disconnect(struct usb_interface *interface)
 	}
 	if (i == MAX_NUM_82357A_INTERFACES)
 		dev_err(&usb_dev->dev, "unable to find interface - bug?\n");
-	usb_put_dev(usb_dev);
 
 	mutex_unlock(&agilent_82357a_hotplug_lock);
 }
-- 
2.52.0

[PATCH 2/2] gpib: ni_usb: 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/gpib/ni_usb/ni_usb_gpib.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/gpib/ni_usb/ni_usb_gpib.c b/drivers/gpib/ni_usb/ni_usb_gpib.c
index a24cd6521362..0bbc13ecebf9 100644
--- a/drivers/gpib/ni_usb/ni_usb_gpib.c
+++ b/drivers/gpib/ni_usb/ni_usb_gpib.c
@@ -2431,7 +2431,6 @@ static int ni_usb_driver_probe(struct usb_interface *interface,	const struct usb
 	static const int path_length = 1024;
 
 	mutex_lock(&ni_usb_hotplug_lock);
-	usb_get_dev(usb_dev);
 	for (i = 0; i < MAX_NUM_NI_USB_INTERFACES; i++) {
 		if (!ni_usb_driver_interfaces[i]) {
 			ni_usb_driver_interfaces[i] = interface;
@@ -2440,14 +2439,12 @@ static int ni_usb_driver_probe(struct usb_interface *interface,	const struct usb
 		}
 	}
 	if (i == MAX_NUM_NI_USB_INTERFACES) {
-		usb_put_dev(usb_dev);
 		mutex_unlock(&ni_usb_hotplug_lock);
 		dev_err(&usb_dev->dev, "ni_usb_driver_interfaces[] full\n");
 		return -1;
 	}
 	path = kmalloc(path_length, GFP_KERNEL);
 	if (!path) {
-		usb_put_dev(usb_dev);
 		mutex_unlock(&ni_usb_hotplug_lock);
 		return -ENOMEM;
 	}
@@ -2488,7 +2485,6 @@ static void ni_usb_driver_disconnect(struct usb_interface *interface)
 	}
 	if (i == MAX_NUM_NI_USB_INTERFACES)
 		dev_err(&usb_dev->dev, "unable to find interface  bug?\n");
-	usb_put_dev(usb_dev);
 	mutex_unlock(&ni_usb_hotplug_lock);
 }
 
-- 
2.52.0