USB: legousbtower: use usb_control_msg_recv()

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>
Link: https://lore.kernel.org/r/20200914153756.3412156-6-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index f922544056de4f071d8240af10b70e37ddc7b1c0..c3583df4c324c512955987ae1ab5ba7b6032e541 100644 (file)
--- 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 @@ unlock_exit:
        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;
 }