input: pxrc - do not store USB device in private struct

PATCH In review Marcus Folkesson 2 participants 4 messages Jul 16, 2018 – Jul 25, 2018

Subsystems (3)

HID Input drivers Phoenix RC flight controller adapter

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Marcus Folkesson

author maintainer

2018-07-16 14:40 UTC #0 lore raw

PATCH 1/1 input: pxrc - do not store USB device in private struct

The USB device is only needed during setup, so put it back after initialization and do not store it in our private struct.

Also, the USB device is a parent of USB interface so our driver model rules ensure that USB device should not disappear while interface device is still there.
So not keep a refcount on the device is safe.

Reported-by Alexey Khoroshilov <[email protected]>

Signed-off-by Marcus Folkesson <[email protected]>

---
 drivers/input/joystick/pxrc.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

drivers/input/joystick/pxrc.c +12 ~~-10~~

index 07a0dbd3ced2..46a7acb747bf 100644
@@ -27,7 +27,6 @@ MODULE_DEVICE_TABLE(usb, pxrc_table);
 
 struct pxrc {
 	struct input_dev	*input;
-	struct usb_device	*udev;
 	struct usb_interface	*intf;
 	struct urb		*urb;
 	struct mutex		pm_mutex;

@@ -120,7 +119,7 @@ static void pxrc_close(struct input_dev *input)
 	mutex_unlock(&pxrc->pm_mutex);
 }
 
-static int pxrc_usb_init(struct pxrc *pxrc)
+static int pxrc_usb_init(struct pxrc *pxrc, struct usb_device *udev)
 {
 	struct usb_endpoint_descriptor *epirq;
 	unsigned int pipe;

@@ -145,7 +144,7 @@ static int pxrc_usb_init(struct pxrc *pxrc)
 	}
 
 	usb_set_intfdata(pxrc->intf, pxrc);
-	usb_make_path(pxrc->udev, pxrc->phys, sizeof(pxrc->phys));
+	usb_make_path(udev, pxrc->phys, sizeof(pxrc->phys));
 	strlcat(pxrc->phys, "/input0", sizeof(pxrc->phys));
 
 	pxrc->urb = usb_alloc_urb(0, GFP_KERNEL);

@@ -154,8 +153,8 @@ static int pxrc_usb_init(struct pxrc *pxrc)
 		goto error;
 	}
 
-	pipe = usb_rcvintpipe(pxrc->udev, pxrc->epaddr),
-	usb_fill_int_urb(pxrc->urb, pxrc->udev, pipe, pxrc->data, pxrc->bsize,
+	pipe = usb_rcvintpipe(udev, pxrc->epaddr),
+	usb_fill_int_urb(pxrc->urb, udev, pipe, pxrc->data, pxrc->bsize,
 						pxrc_usb_irq, pxrc, 1);
 
 error:

@@ -164,7 +163,7 @@ static int pxrc_usb_init(struct pxrc *pxrc)
 
 }
 
-static int pxrc_input_init(struct pxrc *pxrc)
+static int pxrc_input_init(struct pxrc *pxrc, struct usb_device *udev)
 {
 	pxrc->input = devm_input_allocate_device(&pxrc->intf->dev);
 	if (pxrc->input == NULL) {

@@ -174,7 +173,7 @@ static int pxrc_input_init(struct pxrc *pxrc)
 
 	pxrc->input->name = "PXRC Flight Controller Adapter";
 	pxrc->input->phys = pxrc->phys;
-	usb_to_input_id(pxrc->udev, &pxrc->input->id);
+	usb_to_input_id(udev, &pxrc->input->id);
 
 	pxrc->input->open = pxrc_open;
 	pxrc->input->close = pxrc_close;

@@ -197,6 +196,7 @@ static int pxrc_probe(struct usb_interface *intf,
 		      const struct usb_device_id *id)
 {
 	struct pxrc *pxrc;
+	struct usb_device *udev;
 	int retval;
 
 	pxrc = devm_kzalloc(&intf->dev, sizeof(*pxrc), GFP_KERNEL);

@@ -204,23 +204,25 @@ static int pxrc_probe(struct usb_interface *intf,
 		return -ENOMEM;
 
 	mutex_init(&pxrc->pm_mutex);
-	pxrc->udev = usb_get_dev(interface_to_usbdev(intf));
+	udev = usb_get_dev(interface_to_usbdev(intf));
 	pxrc->intf = intf;
 
-	retval = pxrc_usb_init(pxrc);
+	retval = pxrc_usb_init(pxrc, udev);
 	if (retval)
 		goto error;
 
-	retval = pxrc_input_init(pxrc);
+	retval = pxrc_input_init(pxrc, udev);
 	if (retval)
 		goto err_free_urb;
 
+	usb_put_dev(udev);
 	return 0;
 
 err_free_urb:
 	usb_free_urb(pxrc->urb);
 
 error:
+	usb_put_dev(udev);
 	return retval;
 }

Signature · 1 line

2.18.0

Dmitry Torokhov

maintainer

2018-07-24 02:38 UTC #1 lore raw

Hi Marcus,

Quoted 18 lines · Marcus Folkesson

The USB device is only needed during setup, so put it back after initialization and do not store it in our private struct.
Also, the USB device is a parent of USB interface so our driver model rules ensure that USB device should not disappear while interface device is still there.
So not keep a refcount on the device is safe.
Reported-by Alexey Khoroshilov <[email protected]>
Signed-off-by Marcus Folkesson <[email protected]>
---
 drivers/input/joystick/pxrc.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)
drivers/input/joystick/pxrc.c +0 -0
index 07a0dbd3ced2..46a7acb747bf 100644

...

drivers/input/joystick/pxrc.c static int pxrc_probe(struct usb_interface *intf, · line 207

Quoted 6 lines

drivers/input/joystick/pxrc.c +1 -1

@@ -204,23 +204,25 @@ static int pxrc_probe(struct usb_interface *intf,
 		return -ENOMEM;
 
 	mutex_init(&pxrc->pm_mutex);
-	pxrc->udev = usb_get_dev(interface_to_usbdev(intf));
+	udev = usb_get_dev(interface_to_usbdev(intf));

There is really no need to "get" device for the probe duration, or in general, when you are not storing the reference to it.

I posted series with an updated version of this patch plus couple more cleanups/fixes, and would appreciate if you could give it a spin.

Thanks.

Signature · 1 line

Dmitry

Marcus Folkesson

author maintainer Reviewed-by Tested-by

2018-07-24 18:09 UTC #2 lore raw

Hello Dmitry,

Quoted 33 lines · Dmitry Torokhov

Hi Marcus,
Quoted 18 lines · Marcus Folkesson
The USB device is only needed during setup, so put it back after initialization and do not store it in our private struct.
Also, the USB device is a parent of USB interface so our driver model rules ensure that USB device should not disappear while interface device is still there.
So not keep a refcount on the device is safe.
Reported-by Alexey Khoroshilov <[email protected]>
Signed-off-by Marcus Folkesson <[email protected]>
---
 drivers/input/joystick/pxrc.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)
drivers/input/joystick/pxrc.c +0 -0
index 07a0dbd3ced2..46a7acb747bf 100644
...
drivers/input/joystick/pxrc.c static int pxrc_probe(struct usb_interface *intf, · line 207
Quoted 6 lines
drivers/input/joystick/pxrc.c +1 -1
@@ -204,23 +204,25 @@ static int pxrc_probe(struct usb_interface *intf,
 		return -ENOMEM;
 
 	mutex_init(&pxrc->pm_mutex);
-	pxrc->udev = usb_get_dev(interface_to_usbdev(intf));
+	udev = usb_get_dev(interface_to_usbdev(intf));
There is really no need to "get" device for the probe duration, or in general, when you are not storing the reference to it.

Quoted 2 lines

I posted series with an updated version of this patch plus couple more cleanups/fixes, and would appreciate if you could give it a spin.

Thank you for doing this.

I have reviewed the patchset and tested on real hardware, and it looks good to me.

For what it's worth:

Reviewed-by Marcus Folkesson <[email protected]>

Tested-by Marcus Folkesson <[email protected]>

On the whole patchset.

Quoted 5 lines

Thanks.
Signature · 1 line
Dmitry

Best regards
Marcus Folkesson

Dmitry Torokhov

maintainer

2018-07-25 23:37 UTC #3 lore raw

Quoted 44 lines · Marcus Folkesson

Hello Dmitry,
Quoted 33 lines · Dmitry Torokhov
Hi Marcus,
Quoted 18 lines · Marcus Folkesson
The USB device is only needed during setup, so put it back after initialization and do not store it in our private struct.
Also, the USB device is a parent of USB interface so our driver model rules ensure that USB device should not disappear while interface device is still there.
So not keep a refcount on the device is safe.
Reported-by Alexey Khoroshilov <[email protected]>
Signed-off-by Marcus Folkesson <[email protected]>
---
 drivers/input/joystick/pxrc.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)
drivers/input/joystick/pxrc.c +0 -0
index 07a0dbd3ced2..46a7acb747bf 100644
...
drivers/input/joystick/pxrc.c static int pxrc_probe(struct usb_interface *intf, · line 207
Quoted 6 lines
drivers/input/joystick/pxrc.c +1 -1
@@ -204,23 +204,25 @@ static int pxrc_probe(struct usb_interface *intf,
 		return -ENOMEM;
 
 	mutex_init(&pxrc->pm_mutex);
-	pxrc->udev = usb_get_dev(interface_to_usbdev(intf));
+	udev = usb_get_dev(interface_to_usbdev(intf));
There is really no need to "get" device for the probe duration, or in general, when you are not storing the reference to it.
Quoted 2 lines
I posted series with an updated version of this patch plus couple more cleanups/fixes, and would appreciate if you could give it a spin.
Thank you for doing this.
I have reviewed the patchset and tested on real hardware, and it looks good to me.

Quoted 6 lines

For what it's worth:
Reviewed-by Marcus Folkesson <[email protected]>
Tested-by Marcus Folkesson <[email protected]>
On the whole patchset.

Excellent, thank you.

Signature · 1 line

Dmitry