staging: r8188eu: remove shared buffer for USB requests

Remove the shared buffer for USB requests because it is not necessary
and use a local on stack variable since the new Core USB API does not
have the constraints of usb_control_msg().

Co-developed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/20210924122705.3781-16-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/hal/usb_ops_linux.c

@@ -14,7 +14,7 @@ static int usb_read(struct intf_hdl *intf, u16 value, void *data, u8 size)
 	struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
 	struct usb_device *udev = dvobjpriv->pusbdev;
 	int status;
-	u8 *io_buf; /* Pointer to I/O buffer */
+	u8 io_buf[4];
 
 	mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
 
@@ -23,9 +23,6 @@ static int usb_read(struct intf_hdl *intf, u16 value, void *data, u8 size)
 		goto mutex_unlock;
 	}
 
-	/*  Acquire IO memory for vendorreq */
-	io_buf = dvobjpriv->usb_vendor_req_buf;
-
 	status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
 				      REALTEK_USB_VENQT_READ, value,
 				      REALTEK_USB_VENQT_CMD_IDX, io_buf,
@@ -70,14 +67,14 @@ static int usb_write(struct intf_hdl *intf, u16 value, void *data, u8 size)
 	struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
 	struct usb_device *udev = dvobjpriv->pusbdev;
 	int status;
-	u8 *io_buf; /* Pointer to I/O buffer */
+	u8 io_buf[VENDOR_CMD_MAX_DATA_LEN];
 
 	mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
 
-	if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx)
-		return -EPERM;
-
-	io_buf = dvobjpriv->usb_vendor_req_buf;
+	if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx) {
+		status = -EPERM;
+		goto mutex_unlock;
+	}
 
 	memcpy(io_buf, data, size);
 	status = usb_control_msg_send(udev, 0, REALTEK_USB_VENQT_CMD_REQ,

drivers/staging/r8188eu/include/drv_types.h

@@ -168,9 +168,6 @@ struct dvobj_priv {
 	struct semaphore usb_suspend_sema;
 	struct mutex  usb_vendor_req_mutex;
 
-	u8 *usb_alloc_vendor_req_buf;
-	u8 *usb_vendor_req_buf;
-
 	struct usb_interface *pusbintf;
 	struct usb_device *pusbdev;
 

drivers/staging/r8188eu/os_dep/usb_intf.c

@@ -75,24 +75,12 @@ static struct rtw_usb_drv *usb_drv = &rtl8188e_usb_drv;
 
 static u8 rtw_init_intf_priv(struct dvobj_priv *dvobj)
 {
-	u8 rst = _SUCCESS;
-
 	mutex_init(&dvobj->usb_vendor_req_mutex);
-
-	dvobj->usb_alloc_vendor_req_buf = kzalloc(MAX_USB_IO_CTL_SIZE, GFP_KERNEL);
-	if (!dvobj->usb_alloc_vendor_req_buf) {
-		DBG_88E("alloc usb_vendor_req_buf failed... /n");
-		rst = _FAIL;
-		goto exit;
-	}
-	dvobj->usb_vendor_req_buf = (u8 *)N_BYTE_ALIGMENT((size_t)(dvobj->usb_alloc_vendor_req_buf), ALIGNMENT_UNIT);
-exit:
-	return rst;
+	return _SUCCESS;
 }
 
 static void rtw_deinit_intf_priv(struct dvobj_priv *dvobj)
 {
-	kfree(dvobj->usb_alloc_vendor_req_buf);
 	mutex_destroy(&dvobj->usb_vendor_req_mutex);
 }