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authorMauro Carvalho Chehab <m.chehab@samsung.com>2013-11-02 06:17:47 -0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-04 11:06:33 -0800
commit02b2645af91699858fbcfa8aa82d19713bfd5567 (patch)
treeafc5126bc6d534b2d870b032b7b46ec0a4a32f4a
parent3f6609e284d382ba41fb32d2bcab49dcd85601ce (diff)
media: cimax2: Don't use dynamic static allocation
commit 278ba83a3a1932805be726bdd7dfb3156286d33a upstream. Dynamic static allocation is evil, as Kernel stack is too low, and compilation complains about it on some archs: drivers/media/pci/cx23885/cimax2.c:149:1: warning: 'netup_write_i2c' 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>
-rw-r--r--drivers/media/pci/cx23885/cimax2.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/media/pci/cx23885/cimax2.c b/drivers/media/pci/cx23885/cimax2.c
index 7344849183a7..16fa7ea4d4aa 100644
--- a/drivers/media/pci/cx23885/cimax2.c
+++ b/drivers/media/pci/cx23885/cimax2.c
@@ -26,6 +26,10 @@
#include "cx23885.h"
#include "cimax2.h"
#include "dvb_ca_en50221.h"
+
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
/**** Bit definitions for MC417_RWD and MC417_OEN registers ***
bits 31-16
+-----------+
@@ -125,7 +129,7 @@ static int netup_write_i2c(struct i2c_adapter *i2c_adap, u8 addr, u8 reg,
u8 *buf, int len)
{
int ret;
- u8 buffer[len + 1];
+ u8 buffer[MAX_XFER_SIZE];
struct i2c_msg msg = {
.addr = addr,
@@ -134,6 +138,13 @@ static int netup_write_i2c(struct i2c_adapter *i2c_adap, u8 addr, u8 reg,
.len = len + 1
};
+ if (1 + len > sizeof(buffer)) {
+ printk(KERN_WARNING
+ "%s: i2c wr reg=%04x: len=%d is too big!\n",
+ KBUILD_MODNAME, reg, len);
+ return -EINVAL;
+ }
+
buffer[0] = reg;
memcpy(&buffer[1], buf, len);