[PATCH 3.10 140/173] media: mxl111sf: Dont use dynamic static allocation

Greg Kroah-Hartman
2013-12-02T19:12:03Z

From: Mauro Carvalho Chehab <m.chehab@samsung.com>

commit c98300a0e8cf160aaea60bc05d2cd156a7666173 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/usb/dvb-usb-v2/mxl111sf.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- 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 "
@@ -63,7 +66,12 @@ int mxl111sf_ctrl_msg(struct dvb_usb_dev
{
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;
+ }

deb_adv("%s(wlen = %d, rlen = %d)\n", __func__, wlen, rlen);