Skip to contentSkip to conversation

tablet: acecad: update the reference count of the usb interface structure

PATCH In review Salah Triki 3 participants 4 messages Jul 31, 2021 – Aug 4, 2021

Subsystems (2)
Staging Input drivers
lore
Share & tools
lore

Salah Triki

author
#0 lore raw

PATCH v2 1/1 tablet: acecad: update the reference count of the usb interface structure

Based on the following documentation usb_get_inf(), use usb_get_intf() and usb_put_intf() in order to update the reference count of the usb interface structure.

Documentation of usb_get_inf():

[quote]
Each live reference to a interface must be refcounted.

Drivers for USB interfaces should normally record such references in their probe methods, when they bind to an interface, and release them by calling usb_put_intf, in their disconnect methods. [/quote]

Signed-off-by Salah Triki <[email protected]>

---
Change since v1:
Modification of the description

 drivers/input/tablet/acecad.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
drivers/input/tablet/acecad.c +4 -1
index a38d1fe97334..85fe134a30ee 100644
@@ -151,7 +151,7 @@ static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_
 		goto fail2;
 	}
 
-	acecad->intf = intf;
+	acecad->intf = usb_get_intf(intf);
 	acecad->input = input_dev;
 
 	if (dev->manufacturer)

@@ -236,6 +236,9 @@ static void usb_acecad_disconnect(struct usb_interface *intf)
 	input_unregister_device(acecad->input);
 	usb_free_urb(acecad->irq);
 	usb_free_coherent(udev, 8, acecad->data, acecad->data_dma);
+
+	usb_put_intf(acecad->intf);
+
 	kfree(acecad);
 }
Signature · 1 line
2.25.1
#1 lore raw
Quoted 8 lines · Salah Triki
 drivers/input/tablet/acecad.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
drivers/input/tablet/acecad.c +0 -0
index a38d1fe97334..85fe134a30ee 100644

drivers/input/tablet/acecad.c static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_ · line 157

Quoted 8 lines
drivers/input/tablet/acecad.c +1 -1
@@ -151,7 +151,7 @@ static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_
 		goto fail2;
 	}
 
-	acecad->intf = intf;
+	acecad->intf = usb_get_intf(intf);
 	acecad->input = input_dev;
 
 	if (dev->manufacturer)

As I mentioned earlier, you need to drop the reference if input_register_device() fails.

regards,
dan carpenter

maintainer
#2 lore raw
Quoted 12 lines · Dan Carpenter
Quoted 11 lines · Salah Triki
 drivers/input/tablet/acecad.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
drivers/input/tablet/acecad.c +0 -0
index a38d1fe97334..85fe134a30ee 100644
@@ -151,7 +151,7 @@ static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_
 		goto fail2;
 	}
Quoted 8 lines

drivers/input/tablet/acecad.c static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_ · line 157

Quoted 5 lines
drivers/input/tablet/acecad.c +1 -1
-	acecad->intf = intf;
+	acecad->intf = usb_get_intf(intf);
 	acecad->input = input_dev;
 
 	if (dev->manufacturer)

As I mentioned earlier, you need to drop the reference if input_register_device() fails.

Also as mentioned in other threads, this is not needed at all.

#3 lore raw
In reply to Salah Triki
Quoted 9 lines · Salah Triki

Based on the following documentation usb_get_inf(), use usb_get_intf() and usb_put_intf() in order to update the reference count of the usb interface structure.

Documentation of usb_get_inf():

[quote]
Each live reference to a interface must be refcounted.

Quoted 6 lines

Drivers for USB interfaces should normally record such references in their probe methods, when they bind to an interface, and release them by calling usb_put_intf, in their disconnect methods. [/quote]

Signed-off-by Salah Triki <[email protected]>

Also add a Fixes tag.

regards,
dan carpenter