[PATCH v2 05/11] USB: legousbtower: use usb_control_msg_recv()

Greg Kroah-Hartman
2020-09-07T15:53:33Z

The usb_control_msg_recv() function can handle data on the stack, as
well as properly detecting short reads, so move to use that function
instead of the older usb_control_msg() call. This ends up removing a
lot of extra lines in the driver.

Cc: Juergen Stuber <starblue@users.sourceforge.net>
Cc: legousb-devel@lists.sourceforge.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v2:
- no change from v1

drivers/usb/misc/legousbtower.c | 60 +++++++++++----------------------
1 file changed, 19 insertions(+), 41 deletions(-)

diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index f922544056de..c3583df4c324 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -308,15 +308,9 @@ static int tower_open(struct inode *inode, struct file *file)
int subminor;
int retval = 0;
struct usb_interface *interface;
- struct tower_reset_reply *reset_reply;
+ struct tower_reset_reply reset_reply;
int result;

- reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
- if (!reset_reply) {
- retval = -ENOMEM;
- goto exit;
- }
-
nonseekable_open(inode, file);
subminor = iminor(inode);

@@ -347,15 +341,11 @@ static int tower_open(struct inode *inode, struct file *file)
}

/* reset the tower */
- result = usb_control_msg(dev->udev,
- usb_rcvctrlpipe(dev->udev, 0),
- LEGO_USB_TOWER_REQUEST_RESET,
- USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
- 0,
- 0,
- reset_reply,
- sizeof(*reset_reply),
- 1000);
+ result = usb_control_msg_recv(dev->udev, 0,
+ LEGO_USB_TOWER_REQUEST_RESET,
+ USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
+ 0, 0,
+ &reset_reply, sizeof(reset_reply), 1000);
if (result < 0) {
dev_err(&dev->udev->dev,
"LEGO USB Tower reset control request failed\n");
@@ -394,7 +384,6 @@ static int tower_open(struct inode *inode, struct file *file)
mutex_unlock(&dev->lock);

exit:
- kfree(reset_reply);
return retval;
}

@@ -753,7 +742,7 @@ static int tower_probe(struct usb_interface *interface, const struct usb_device_
struct device *idev = &interface->dev;
struct usb_device *udev = interface_to_usbdev(interface);
struct lego_usb_tower *dev;
- struct tower_get_version_reply *get_version_reply = NULL;
+ struct tower_get_version_reply get_version_reply;
int retval = -ENOMEM;
int result;

@@ -798,34 +787,25 @@ static int tower_probe(struct usb_interface *interface, const struct usb_device_
dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;

- get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
- if (!get_version_reply) {
- retval = -ENOMEM;
- goto error;
- }
-
/* get the firmware version and log it */
- result = usb_control_msg(udev,
- usb_rcvctrlpipe(udev, 0),
- LEGO_USB_TOWER_REQUEST_GET_VERSION,
- USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
- 0,
- 0,
- get_version_reply,
- sizeof(*get_version_reply),
- 1000);
- if (result != sizeof(*get_version_reply)) {
- if (result >= 0)
- result = -EIO;
+ result = usb_control_msg_recv(udev, 0,
+ LEGO_USB_TOWER_REQUEST_GET_VERSION,
+ USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
+ 0,
+ 0,
+ &get_version_reply,
+ sizeof(get_version_reply),
+ 1000);
+ if (!result) {
dev_err(idev, "get version request failed: %d\n", result);
retval = result;
goto error;
}
dev_info(&interface->dev,
"LEGO USB Tower firmware version is %d.%d build %d\n",
- get_version_reply->major,
- get_version_reply->minor,
- le16_to_cpu(get_version_reply->build_no));
+ get_version_reply.major,
+ get_version_reply.minor,
+ le16_to_cpu(get_version_reply.build_no));

/* we can register the device now, as it is ready */
usb_set_intfdata(interface, dev);
@@ -844,11 +824,9 @@ static int tower_probe(struct usb_interface *interface, const struct usb_device_
USB_MAJOR, dev->minor);

exit:
- kfree(get_version_reply);
return retval;

error:
- kfree(get_version_reply);
tower_delete(dev);
return retval;
}
--
2.28.0