1 files changed, 94 insertions, 79 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index fcbad9e86328..91abcd904d04 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4741,6 +4741,67 @@ static int hub_enable_device(struct usb_device *udev)
 	return hcd->driver->enable_device(hcd, udev);
 }
 
+/*
+ * Get the bMaxPacketSize0 value during initialization by reading the
+ * device's device descriptor.  Since we don't already know this value,
+ * the transfer is unsafe and it ignores I/O errors, only testing for
+ * reasonable received values.
+ *
+ * For "old scheme" initialization, size will be 8 so we read just the
+ * start of the device descriptor, which should work okay regardless of
+ * the actual bMaxPacketSize0 value.  For "new scheme" initialization,
+ * size will be 64 (and buf will point to a sufficiently large buffer),
+ * which might not be kosher according to the USB spec but it's what
+ * Windows does and what many devices expect.
+ *
+ * Returns: bMaxPacketSize0 or a negative error code.
+ */
+static int get_bMaxPacketSize0(struct usb_device *udev,
+		struct usb_device_descriptor *buf, int size, bool first_time)
+{
+	int i, rc;
+
+	/*
+	 * Retry on all errors; some devices are flakey.
+	 * 255 is for WUSB devices, we actually need to use
+	 * 512 (WUSB1.0[4.8.1]).
+	 */
+	for (i = 0; i < GET_MAXPACKET0_TRIES; ++i) {
+		/* Start with invalid values in case the transfer fails */
+		buf->bDescriptorType = buf->bMaxPacketSize0 = 0;
+		rc = usb_control_msg(udev, usb_rcvaddr0pipe(),
+				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+				USB_DT_DEVICE << 8, 0,
+				buf, size,
+				initial_descriptor_timeout);
+		switch (buf->bMaxPacketSize0) {
+		case 8: case 16: case 32: case 64: case 255:
+			if (buf->bDescriptorType == USB_DT_DEVICE) {
+				rc = buf->bMaxPacketSize0;
+				break;
+			}
+			fallthrough;
+		default:
+			if (rc >= 0)
+				rc = -EPROTO;
+			break;
+		}
+
+		/*
+		 * Some devices time out if they are powered on
+		 * when already connected. They need a second
+		 * reset, so return early. But only on the first
+		 * attempt, lest we get into a time-out/reset loop.
+		 */
+		if (rc > 0 || (rc == -ETIMEDOUT && first_time &&
+				udev->speed > USB_SPEED_FULL))
+			break;
+	}
+	return rc;
+}
+
+#define GET_DESCRIPTOR_BUFSIZE	64
+
 /* Reset device, (re)assign address, get device descriptor.
  * Device connection must be stable, no more debouncing needed.
  * Returns device in USB_STATE_ADDRESS, except on error.
@@ -4765,6 +4826,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 	int			devnum = udev->devnum;
 	const char		*driver_name;
 	bool			do_new_scheme;
+	int			maxp0;
+	struct usb_device_descriptor	*buf;
+
+	buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
+	if (!buf)
+		return -ENOMEM;
 
 	/* root hub ports have a slightly longer reset period
 	 * (from USB 2.0 spec, section 7.1.7.5)
@@ -4884,9 +4951,6 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 		}
 
 		if (do_new_scheme) {
-			struct usb_device_descriptor *buf;
-			int r = 0;
-
 			retval = hub_enable_device(udev);
 			if (retval < 0) {
 				dev_err(&udev->dev,
@@ -4895,52 +4959,8 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 				goto fail;
 			}
 
-#define GET_DESCRIPTOR_BUFSIZE	64
-			buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
-			if (!buf) {
-				retval = -ENOMEM;
-				continue;
-			}
-
-			/* Retry on all errors; some devices are flakey.
-			 * 255 is for WUSB devices, we actually need to use
-			 * 512 (WUSB1.0[4.8.1]).
-			 */
-			for (operations = 0; operations < GET_MAXPACKET0_TRIES;
-					++operations) {
-				buf->bMaxPacketSize0 = 0;
-				r = usb_control_msg(udev, usb_rcvaddr0pipe(),
-					USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
-					USB_DT_DEVICE << 8, 0,
-					buf, GET_DESCRIPTOR_BUFSIZE,
-					initial_descriptor_timeout);
-				switch (buf->bMaxPacketSize0) {
-				case 8: case 16: case 32: case 64: case 255:
-					if (buf->bDescriptorType ==
-							USB_DT_DEVICE) {
-						r = 0;
-						break;
-					}
-					fallthrough;
-				default:
-					if (r == 0)
-						r = -EPROTO;
-					break;
-				}
-				/*
-				 * Some devices time out if they are powered on
-				 * when already connected. They need a second
-				 * reset. But only on the first attempt,
-				 * lest we get into a time out/reset loop
-				 */
-				if (r == 0 || (r == -ETIMEDOUT &&
-						retries == 0 &&
-						udev->speed > USB_SPEED_FULL))
-					break;
-			}
-			udev->descriptor.bMaxPacketSize0 =
-					buf->bMaxPacketSize0;
-			kfree(buf);
+			maxp0 = get_bMaxPacketSize0(udev, buf,
+					GET_DESCRIPTOR_BUFSIZE, retries == 0);
 
 			retval = hub_port_reset(hub, port1, udev, delay, false);
 			if (retval < 0)		/* error or disconnect */
@@ -4951,14 +4971,13 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 				retval = -ENODEV;
 				goto fail;
 			}
-			if (r) {
-				if (r != -ENODEV)
+			if (maxp0 < 0) {
+				if (maxp0 != -ENODEV)
 					dev_err(&udev->dev, "device descriptor read/64, error %d\n",
-							r);
-				retval = -EMSGSIZE;
+							maxp0);
+				retval = maxp0;
 				continue;
 			}
-#undef GET_DESCRIPTOR_BUFSIZE
 		}
 
 		/*
@@ -5004,19 +5023,17 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 				break;
 		}
 
-		retval = usb_get_device_descriptor(udev, 8);
-		if (retval < 8) {
+		/* !do_new_scheme || wusb */
+		maxp0 = get_bMaxPacketSize0(udev, buf, 8, retries == 0);
+		if (maxp0 < 0) {
+			retval = maxp0;
 			if (retval != -ENODEV)
 				dev_err(&udev->dev,
 					"device descriptor read/8, error %d\n",
 					retval);
-			if (retval >= 0)
-				retval = -EMSGSIZE;
 		} else {
 			u32 delay;
 
-			retval = 0;
-
 			delay = udev->parent->hub_delay;
 			udev->hub_delay = min_t(u32, delay,
 						USB_TP_TRANSMISSION_DELAY_MAX);
@@ -5033,27 +5050,10 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 	if (retval)
 		goto fail;
 
-	/*
-	 * Some superspeed devices have finished the link training process
-	 * and attached to a superspeed hub port, but the device descriptor
-	 * got from those devices show they aren't superspeed devices. Warm
-	 * reset the port attached by the devices can fix them.
-	 */
-	if ((udev->speed >= USB_SPEED_SUPER) &&
-			(le16_to_cpu(udev->descriptor.bcdUSB) < 0x0300)) {
-		dev_err(&udev->dev, "got a wrong device descriptor, "
-				"warm reset device\n");
-		hub_port_reset(hub, port1, udev,
-				HUB_BH_RESET_TIME, true);
-		retval = -EINVAL;
-		goto fail;
-	}
-
-	if (udev->descriptor.bMaxPacketSize0 == 0xff ||
-			udev->speed >= USB_SPEED_SUPER)
+	if (maxp0 == 0xff || udev->speed >= USB_SPEED_SUPER)
 		i = 512;
 	else
-		i = udev->descriptor.bMaxPacketSize0;
+		i = maxp0;
 	if (usb_endpoint_maxp(&udev->ep0.desc) != i) {
 		if (udev->speed == USB_SPEED_LOW ||
 				!(i == 8 || i == 16 || i == 32 || i == 64)) {
@@ -5079,6 +5079,20 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 		goto fail;
 	}
 
+	/*
+	 * Some superspeed devices have finished the link training process
+	 * and attached to a superspeed hub port, but the device descriptor
+	 * got from those devices show they aren't superspeed devices. Warm
+	 * reset the port attached by the devices can fix them.
+	 */
+	if ((udev->speed >= USB_SPEED_SUPER) &&
+			(le16_to_cpu(udev->descriptor.bcdUSB) < 0x0300)) {
+		dev_err(&udev->dev, "got a wrong device descriptor, warm reset device\n");
+		hub_port_reset(hub, port1, udev, HUB_BH_RESET_TIME, true);
+		retval = -EINVAL;
+		goto fail;
+	}
+
 	usb_detect_quirks(udev);
 
 	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
@@ -5101,6 +5115,7 @@ fail:
 		hub_port_disable(hub, port1, 0);
 		update_devnum(udev, devnum);	/* for disconnect processing */
 	}
+	kfree(buf);
 	return retval;
 }