rtlwifi: usb: allocate URB control message setup_packet and data buffer separately

rtlwifi allocates both setup_packet and data buffer of control message urb,
using shared kmalloc in _usbctrl_vendorreq_async_write. Structure used for
allocating is:
	struct {
		u8 data[254];
		struct usb_ctrlrequest dr;
	};

Because 'struct usb_ctrlrequest' is __packed, setup packet is unaligned and
DMA mapping of both 'data' and 'dr' confuses ARM/sunxi, leading to memory
corruptions and freezes.

Patch changes setup packet to be allocated separately.

[v2]:
 - Use WARN_ON_ONCE instead of WARN_ON

Cc: <stable@vger.kernel.org>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 16 deletions

diff --git a/drivers/net/wireless/rtlwifi/usb.c b/drivers/net/wireless/rtlwifi/usb.c
index 476eaef5e4a9..156b52732f3d 100644
--- a/drivers/net/wireless/rtlwifi/usb.c
+++ b/drivers/net/wireless/rtlwifi/usb.c
@@ -42,8 +42,12 @@
 
 static void usbctrl_async_callback(struct urb *urb)
 {
-        if (urb)
-                kfree(urb->context);
+        if (urb) {
+                /* free dr */
+                kfree(urb->setup_packet);
+                /* free databuf */
+                kfree(urb->transfer_buffer);
+        }
 }
 
 static int _usbctrl_vendorreq_async_write(struct usb_device *udev, u8 request,
@@ -55,39 +59,47 @@ static int _usbctrl_vendorreq_async_write(struct usb_device *udev, u8 request,
         u8 reqtype;
         struct usb_ctrlrequest *dr;
         struct urb *urb;
-        struct rtl819x_async_write_data {
-                u8 data[REALTEK_USB_VENQT_MAX_BUF_SIZE];
-                struct usb_ctrlrequest dr;
-        } *buf;
+        const u16 databuf_maxlen = REALTEK_USB_VENQT_MAX_BUF_SIZE;
+        u8 *databuf;
+
+        if (WARN_ON_ONCE(len > databuf_maxlen))
+                len = databuf_maxlen;
 
         pipe = usb_sndctrlpipe(udev, 0); /* write_out */
         reqtype =  REALTEK_USB_VENQT_WRITE;
 
-        buf = kmalloc(sizeof(*buf), GFP_ATOMIC);
-        if (!buf)
+        dr = kmalloc(sizeof(*dr), GFP_ATOMIC);
+        if (!dr)
                 return -ENOMEM;
 
+        databuf = kmalloc(databuf_maxlen, GFP_ATOMIC);
+        if (!databuf) {
+                kfree(dr);
+                return -ENOMEM;
+        }
+
         urb = usb_alloc_urb(0, GFP_ATOMIC);
         if (!urb) {
-                kfree(buf);
+                kfree(databuf);
+                kfree(dr);
                 return -ENOMEM;
         }
 
-        dr = &buf->dr;
-
         dr->bRequestType = reqtype;
         dr->bRequest = request;
         dr->wValue = cpu_to_le16(value);
         dr->wIndex = cpu_to_le16(index);
         dr->wLength = cpu_to_le16(len);
         /* data are already in little-endian order */
-        memcpy(buf, pdata, len);
+        memcpy(databuf, pdata, len);
         usb_fill_control_urb(urb, udev, pipe,
-                             (unsigned char *)dr, buf, len,
-                             usbctrl_async_callback, buf);
+                             (unsigned char *)dr, databuf, len,
+                             usbctrl_async_callback, NULL);
         rc = usb_submit_urb(urb, GFP_ATOMIC);
-        if (rc < 0)
-                kfree(buf);
+        if (rc < 0) {
+                kfree(databuf);
+                kfree(dr);
+        }
         usb_free_urb(urb);
         return rc;
 }