[media] opera1: get rid of on-stack dma buffer

usb_control_msg initiates (and waits for completion of) a dma transfer using
the supplied buffer. That buffer thus has to be seperately allocated on
the heap.

In lib/dma_debug.c the function check_for_stack even warns about it:
	WARNING: at lib/dma-debug.c:866 check_for_stack

Note: This change is tested to compile only, as I don't have the hardware.

Signed-off-by: Florian Mickler <florian@mickler.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/media/dvb/dvb-usb/opera1.c b/drivers/media/dvb/dvb-usb/opera1.c
index 7e569f4dd80..4258f127ea3 100644
--- a/drivers/media/dvb/dvb-usb/opera1.c
+++ b/drivers/media/dvb/dvb-usb/opera1.c
@@ -53,27 +53,36 @@ static int opera1_xilinx_rw(struct usb_device *dev, u8 request, u16 value,
                             u8 * data, u16 len, int flags)
 {
         int ret;
-        u8 r;
-        u8 u8buf[len];
-
+        u8 tmp;
+        u8 *buf;
         unsigned int pipe = (flags == OPERA_READ_MSG) ?
                 usb_rcvctrlpipe(dev,0) : usb_sndctrlpipe(dev, 0);
         u8 request_type = (flags == OPERA_READ_MSG) ? USB_DIR_IN : USB_DIR_OUT;
 
+        buf = kmalloc(len, GFP_KERNEL);
+        if (!buf)
+                return -ENOMEM;
+
         if (flags == OPERA_WRITE_MSG)
-                memcpy(u8buf, data, len);
-        ret =
-                usb_control_msg(dev, pipe, request, request_type | USB_TYPE_VENDOR,
-                        value, 0x0, u8buf, len, 2000);
+                memcpy(buf, data, len);
+        ret = usb_control_msg(dev, pipe, request,
+                        request_type | USB_TYPE_VENDOR, value, 0x0,
+                        buf, len, 2000);
 
         if (request == OPERA_TUNER_REQ) {
+                tmp = buf[0];
                 if (usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
-                                OPERA_TUNER_REQ, USB_DIR_IN | USB_TYPE_VENDOR,
-                                0x01, 0x0, &r, 1, 2000)<1 || r!=0x08)
-                                        return 0;
+                            OPERA_TUNER_REQ, USB_DIR_IN | USB_TYPE_VENDOR,
+                            0x01, 0x0, buf, 1, 2000) < 1 || buf[0] != 0x08) {
+                        ret = 0;
+                        goto out;
+                }
+                buf[0] = tmp;
         }
         if (flags == OPERA_READ_MSG)
-                memcpy(data, u8buf, len);
+                memcpy(data, buf, len);
+out:
+        kfree(buf);
         return ret;
 }