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authorMauro Carvalho Chehab <m.chehab@samsung.com>2013-11-02 05:11:47 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2013-11-08 09:45:39 -0200
commit37ebaf6891ee81687bb558e8375c0712d8264ed8 (patch)
tree690fd4e54358fa1e6a9db6356a5f1afbc6b59593 /drivers/media/dvb-frontends/tda10071.c
parent8393796dfa4cf5dffcceec464c7789bec3a2f471 (diff)
downloadop-kernel-dev-37ebaf6891ee81687bb558e8375c0712d8264ed8.zip
op-kernel-dev-37ebaf6891ee81687bb558e8375c0712d8264ed8.tar.gz
[media] dvb-frontends: 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/dvb-frontends/af9013.c:77:1: warning: 'af9013_wr_regs_i2c' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/af9033.c:188:1: warning: 'af9033_wr_reg_val_tab' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/af9033.c:68:1: warning: 'af9033_wr_regs' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/bcm3510.c:230:1: warning: 'bcm3510_do_hab_cmd' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/cxd2820r_core.c:84:1: warning: 'cxd2820r_rd_regs_i2c.isra.1' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/rtl2830.c:56:1: warning: 'rtl2830_wr' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/rtl2832.c:187:1: warning: 'rtl2832_wr' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/tda10071.c:52:1: warning: 'tda10071_wr_regs' uses dynamic stack allocation [enabled by default] drivers/media/dvb-frontends/tda10071.c:84:1: warning: 'tda10071_rd_regs' uses dynamic stack allocation [enabled by default] Instead, let's enforce a limit for the buffer. Considering that I2C transfers are generally limited, and that devices used on USB has a max data length of 64 bytes for the control URBs. So, it seem safe to use 64 bytes as the hard limit for all those devices. On most cases, the limit is a way lower than that, but this limit is small enough to not affect the Kernel stack, and it is a no brain limit, as using smaller ones would require to either carefully each driver or to take a look on each datasheet. 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>
Diffstat (limited to 'drivers/media/dvb-frontends/tda10071.c')
-rw-r--r--drivers/media/dvb-frontends/tda10071.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/drivers/media/dvb-frontends/tda10071.c b/drivers/media/dvb-frontends/tda10071.c
index e79749c..8ad3a57 100644
--- a/drivers/media/dvb-frontends/tda10071.c
+++ b/drivers/media/dvb-frontends/tda10071.c
@@ -20,6 +20,9 @@
#include "tda10071_priv.h"
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
static struct dvb_frontend_ops tda10071_ops;
/* write multiple registers */
@@ -27,16 +30,23 @@ static int tda10071_wr_regs(struct tda10071_priv *priv, u8 reg, u8 *val,
int len)
{
int ret;
- u8 buf[len+1];
+ u8 buf[MAX_XFER_SIZE];
struct i2c_msg msg[1] = {
{
.addr = priv->cfg.demod_i2c_addr,
.flags = 0,
- .len = sizeof(buf),
+ .len = 1 + len,
.buf = buf,
}
};
+ if (1 + len > sizeof(buf)) {
+ dev_warn(&priv->i2c->dev,
+ "%s: i2c wr reg=%04x: len=%d is too big!\n",
+ KBUILD_MODNAME, reg, len);
+ return -EINVAL;
+ }
+
buf[0] = reg;
memcpy(&buf[1], val, len);
@@ -56,7 +66,7 @@ static int tda10071_rd_regs(struct tda10071_priv *priv, u8 reg, u8 *val,
int len)
{
int ret;
- u8 buf[len];
+ u8 buf[MAX_XFER_SIZE];
struct i2c_msg msg[2] = {
{
.addr = priv->cfg.demod_i2c_addr,
@@ -66,11 +76,18 @@ static int tda10071_rd_regs(struct tda10071_priv *priv, u8 reg, u8 *val,
}, {
.addr = priv->cfg.demod_i2c_addr,
.flags = I2C_M_RD,
- .len = sizeof(buf),
+ .len = len,
.buf = buf,
}
};
+ if (len > sizeof(buf)) {
+ dev_warn(&priv->i2c->dev,
+ "%s: i2c wr reg=%04x: len=%d is too big!\n",
+ KBUILD_MODNAME, reg, len);
+ return -EINVAL;
+ }
+
ret = i2c_transfer(priv->i2c, msg, 2);
if (ret == 2) {
memcpy(val, buf, len);
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