[media] mxl111sf: Don't use dynamic static allocation

Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
	drivers/media/usb/dvb-usb-v2/mxl111sf.c:74:1: warning: 'mxl111sf_ctrl_msg' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer to be the max size of
a control URB payload data (64 bytes).

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index e97964ef7f56..2627553f7de1 100644
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -23,6 +23,9 @@
 #include "lgdt3305.h"
 #include "lg2160.h"
 
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE  64
+
 int dvb_usb_mxl111sf_debug;
 module_param_named(debug, dvb_usb_mxl111sf_debug, int, 0644);
 MODULE_PARM_DESC(debug, "set debugging level "
@@ -57,7 +60,12 @@ int mxl111sf_ctrl_msg(struct dvb_usb_device *d,
 {
         int wo = (rbuf == NULL || rlen == 0); /* write-only */
         int ret;
-        u8 sndbuf[1+wlen];
+        u8 sndbuf[MAX_XFER_SIZE];
+
+        if (1 + wlen > sizeof(sndbuf)) {
+                pr_warn("%s: len=%d is too big!\n", __func__, wlen);
+                return -EOPNOTSUPP;
+        }
 
         pr_debug("%s(wlen = %d, rlen = %d)\n", __func__, wlen, rlen);