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authorMauro Carvalho Chehab <m.chehab@samsung.com>2013-11-02 05:17:01 -0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-04 11:06:34 -0800
commit30f028d83800c4340e0f309698465a9f364af771 (patch)
parent5d9befae5c21f6831ec5d7d60fc03b190156b444 (diff)
media: stv0367: Don't use dynamic static allocation
commit 9aca4fb0571ce9cfef680ceb08d19dd008015307 upstream. Dynamic static allocation is evil, as Kernel stack is too low, and compilation complains about it on some archs: drivers/media/dvb-frontends/stv0367.c:791:1: warning: 'stv0367_writeregs.constprop.4' 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> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c
index 7b6dba3ce55e..458772739423 100644
--- a/drivers/media/dvb-frontends/stv0367.c
+++ b/drivers/media/dvb-frontends/stv0367.c
@@ -33,6 +33,9 @@
#include "stv0367_regs.h"
#include "stv0367_priv.h"
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
static int stvdebug;
module_param_named(debug, stvdebug, int, 0644);
@@ -767,7 +770,7 @@ static struct st_register def0367cab[STV0367CAB_NBREGS] = {
int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len)
- u8 buf[len + 2];
+ u8 buf[MAX_XFER_SIZE];
struct i2c_msg msg = {
.addr = state->config->demod_address,
.flags = 0,
@@ -776,6 +779,14 @@ int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len)
int ret;
+ if (2 + len > sizeof(buf)) {
+ "%s: i2c wr reg=%04x: len=%d is too big!\n",
+ KBUILD_MODNAME, reg, len);
+ return -EINVAL;
+ }
buf[0] = MSB(reg);
buf[1] = LSB(reg);
memcpy(buf + 2, data, len);