[PATCH 05/10] USB: legousbtower: use usb_control_msg_recv() - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: himadrispandya@gmail.com, dvyukov@google.com, linux-usb@vger.kernel.org
Cc: perex@perex.cz, tiwai@suse.com, stern@rowland.harvard.ed,
	linux-kernel@vger.kernel.org, marcel@holtmann.org,
	johan.hedberg@gmail.com, linux-bluetooth@vger.kernel.org,
	alsa-devel@alsa-project.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Juergen Stuber <starblue@users.sourceforge.net>,
	legousb-devel@lists.sourceforge.net
Subject: [PATCH 05/10] USB: legousbtower: use usb_control_msg_recv()
Date: Wed,  2 Sep 2020 13:01:07 +0200	[thread overview]
Message-ID: <20200902110115.1994491-6-gregkh@linuxfoundation.org> (raw)
In-Reply-To: <20200902110115.1994491-1-gregkh@linuxfoundation.org>

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>
---
 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

