[PATCH 3.10 141/173] media: af9035: Dont use dynamic static allocation

Greg Kroah-Hartman
2013-12-02T19:14:34Z

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

commit 7760e148350bf6df95662bc0db3734e9d991cb03 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/af9035.c:142:1: warning: 'af9035_wr_regs' uses dynamic stack allocation [enabled by default]
drivers/media/usb/dvb-usb-v2/af9035.c:305:1: warning: 'af9035_i2c_master_xfer' 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>
Reviewed-by: Antti Palosaari <crope@iki.fi>
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/af9035.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)

--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -21,6 +21,9 @@

#include "af9035.h"

+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);

static u16 af9035_checksum(const u8 *buf, size_t len)
@@ -125,10 +128,16 @@ exit:
/* write multiple registers */
static int af9035_wr_regs(struct dvb_usb_device *d, u32 reg, u8 *val, int len)
{
- u8 wbuf[6 + len];
+ u8 wbuf[MAX_XFER_SIZE];
u8 mbox = (reg >> 16) & 0xff;
struct usb_req req = { CMD_MEM_WR, mbox, sizeof(wbuf), wbuf, 0, NULL };

+ if (6 + len > sizeof(wbuf)) {
+ dev_warn(&d->udev->dev, "%s: i2c wr: len=%d is too big!\n",
+ KBUILD_MODNAME, len);
+ return -EOPNOTSUPP;
+ }
+
wbuf[0] = len;
wbuf[1] = 2;
wbuf[2] = 0;
@@ -227,9 +236,16 @@ static int af9035_i2c_master_xfer(struct
msg[1].len);
} else {
/* I2C */
- u8 buf[5 + msg[0].len];
+ u8 buf[MAX_XFER_SIZE];
struct usb_req req = { CMD_I2C_RD, 0, sizeof(buf),
buf, msg[1].len, msg[1].buf };
+
+ if (5 + msg[0].len > sizeof(buf)) {
+ dev_warn(&d->udev->dev,
+ "%s: i2c xfer: len=%d is too big!\n",
+ KBUILD_MODNAME, msg[0].len);
+ return -EOPNOTSUPP;
+ }
req.mbox |= ((msg[0].addr & 0x80) >> 3);
buf[0] = msg[1].len;
buf[1] = msg[0].addr << 1;
@@ -256,9 +272,16 @@ static int af9035_i2c_master_xfer(struct
msg[0].len - 3);
} else {
/* I2C */
- u8 buf[5 + msg[0].len];
+ u8 buf[MAX_XFER_SIZE];
struct usb_req req = { CMD_I2C_WR, 0, sizeof(buf), buf,
0, NULL };
+
+ if (5 + msg[0].len > sizeof(buf)) {
+ dev_warn(&d->udev->dev,
+ "%s: i2c xfer: len=%d is too big!\n",
+ KBUILD_MODNAME, msg[0].len);
+ return -EOPNOTSUPP;
+ }
req.mbox |= ((msg[0].addr & 0x80) >> 3);
buf[0] = msg[0].len;
buf[1] = msg[0].addr << 1;