usb: gadget: Introduce free_usb_request helper

Introduce the free_usb_request() function that frees both the request's
buffer and the request itself.

This function serves as the cleanup callback for DEFINE_FREE() to enable
automatic, scope-based cleanup for usb_request pointers.

Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://lore.kernel.org/r/20250916-ready-v1-2-4997bf277548@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250916-ready-v1-2-4997bf277548@google.com

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 0f20794760887314d81a070755c8908c6ac4ed90..3aaf19e775580b19cbb2b30d8df8a282945edfa0 100644 (file)
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -15,6 +15,7 @@
 #ifndef __LINUX_USB_GADGET_H
 #define __LINUX_USB_GADGET_H
 
+#include <linux/cleanup.h>
 #include <linux/configfs.h>
 #include <linux/device.h>
 #include <linux/errno.h>
@@ -293,6 +294,28 @@ static inline void usb_ep_fifo_flush(struct usb_ep *ep)
 
 /*-------------------------------------------------------------------------*/
 
+/**
+ * free_usb_request - frees a usb_request object and its buffer
+ * @req: the request being freed
+ *
+ * This helper function frees both the request's buffer and the request object
+ * itself by calling usb_ep_free_request(). Its signature is designed to be used
+ * with DEFINE_FREE() to enable automatic, scope-based cleanup for usb_request
+ * pointers.
+ */
+static inline void free_usb_request(struct usb_request *req)
+{
+       if (!req)
+               return;
+
+       kfree(req->buf);
+       usb_ep_free_request(req->ep, req);
+}
+
+DEFINE_FREE(free_usb_request, struct usb_request *, free_usb_request(_T))
+
+/*-------------------------------------------------------------------------*/
+
 struct usb_dcd_config_params {
        __u8  bU1devExitLat;    /* U1 Device exit Latency */
 #define USB_DEFAULT_U1_DEV_EXIT_LAT    0x01    /* Less then 1 microsec */