[3.11.y.z extended stable] Patch "[media] s5h1420: Don't use dynamic static allocation" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    [media] s5h1420: Don't use dynamic static allocation

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From f28b8cf97e55d59cff186dd9481794112057fdc0 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <m.chehab at samsung.com>
Date: Sat, 2 Nov 2013 04:29:42 -0300
Subject: [media] s5h1420: Don't use dynamic static allocation

commit 9736a89dafe07359d9c86bf9c3b815a250b354bc upstream.

Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
	drivers/media/dvb-frontends/s5h1420.c:851:1: warning: 's5h1420_tuner_i2c_tuner_xfer' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer.
In the specific case of this frontend, only ttpci uses it. The maximum
number of messages there is two, on I2C read operations. As the logic
can add an extra operation, change the size to 3.

Signed-off-by: Mauro Carvalho Chehab <m.chehab at samsung.com>
Reviewed-by: Hans Verkuil <hans.verkuil at cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab at samsung.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/media/dvb-frontends/s5h1420.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/media/dvb-frontends/s5h1420.c b/drivers/media/dvb-frontends/s5h1420.c
index e2fec9e..93eeaf7 100644
--- a/drivers/media/dvb-frontends/s5h1420.c
+++ b/drivers/media/dvb-frontends/s5h1420.c
@@ -836,9 +836,16 @@ static u32 s5h1420_tuner_i2c_func(struct i2c_adapter *adapter)
 static int s5h1420_tuner_i2c_tuner_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msg[], int num)
 {
 	struct s5h1420_state *state = i2c_get_adapdata(i2c_adap);
-	struct i2c_msg m[1 + num];
+	struct i2c_msg m[3];
 	u8 tx_open[2] = { CON_1, state->CON_1_val | 1 }; /* repeater stops once there was a stop condition */

+	if (1 + num > ARRAY_SIZE(m)) {
+		printk(KERN_WARNING
+		       "%s: i2c xfer: num=%d is too big!\n",
+		       KBUILD_MODNAME, num);
+		return  -EOPNOTSUPP;
+	}
+
 	memset(m, 0, sizeof(struct i2c_msg) * (1 + num));

 	m[0].addr = state->config->demod_address;
@@ -847,7 +854,7 @@ static int s5h1420_tuner_i2c_tuner_xfer(struct i2c_adapter *i2c_adap, struct i2c

 	memcpy(&m[1], msg, sizeof(struct i2c_msg) * num);

-	return i2c_transfer(state->i2c, m, 1+num) == 1 + num ? num : -EIO;
+	return i2c_transfer(state->i2c, m, 1 + num) == 1 + num ? num : -EIO;
 }

 static struct i2c_algorithm s5h1420_tuner_i2c_algo = {
--
1.8.3.2