PATCH 1/1: greybus/usb: handle unspecified lengths in hub_control

["Jose A. Perez de Azpillaga" <azpijr@gmail.com>]

From 1e099b581fe475905509b9d600015ea2500b8cf8 Mon Sep 17 00:00:00 2001
From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
Date: Wed, 11 Feb 2026 22:54:40 +0100
Subject: [PATCH] greybus/usb: handle unspecified lengths in hub_control

Fixes the FIXME in hub_control where response length was not handled correctly.

Signed-off-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>
---
 drivers/staging/greybus/usb.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/greybus/usb.c b/drivers/staging/greybus/usb.c
index 475f24f20cd4..f5f5a4863ddc 100644
--- a/drivers/staging/greybus/usb.c
+++ b/drivers/staging/greybus/usb.c
@@ -105,8 +105,10 @@ static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
 	size_t response_size;
 	int ret;
 
-	/* FIXME: handle unspecified lengths */
-	response_size = sizeof(*response) + wLength;
+	/* Calculate expected response size */
+	response_size = sizeof(*response);
+	if (wLength)
+		response_size += wLength;
 
 	operation = gb_operation_create(dev->connection,
 					GB_USB_TYPE_HUB_CONTROL,
@@ -127,9 +129,13 @@ static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
 		goto out;
 
 	if (wLength) {
-		/* Greybus core has verified response size */
-		response = operation->response->payload;
-		memcpy(buf, response->buf, wLength);
+		size_t actual_size = operation->response->payload_size - sizeof(*response);
+		size_t copy_size = min(wLength, actual_size);
+
+		if (copy_size) {
+			response = operation->response->payload;
+			memcpy(buf, response->buf, copy_size);
+		}
 	}
 out:
 	gb_operation_put(operation);
-- 
2.51.0