[media] horus3a: don't use variable length arrays

The Linux stack is short; we need to be able to count the number
of bytes used at stack on each function. So, we don't like to
use variable-length arrays, as complained by smatch:
	drivers/media/dvb-frontends/horus3a.c:57:19: warning: Variable length array is used.

The max usecase of the driver seems to be 5 bytes + 1 for the
register.

So, let's be safe and allocate 6 bytes for the write buffer.
This should be enough to cover all cases. If not, let's print
an error message.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/dvb-frontends/horus3a.c b/drivers/media/dvb-frontends/horus3a.c
index 46a82dc586d8e660d4d6c6e75106f03882114604..5074305b289ecaf55b9d0641371d6e7d148f7503 100644 (file)
--- a/drivers/media/dvb-frontends/horus3a.c
+++ b/drivers/media/dvb-frontends/horus3a.c
@@ -26,6 +26,8 @@
 #include "horus3a.h"
 #include "dvb_frontend.h"
 
+#define MAX_WRITE_REGSIZE      5
+
 enum horus3a_state {
        STATE_UNKNOWN,
        STATE_SLEEP,
@@ -54,16 +56,22 @@ static int horus3a_write_regs(struct horus3a_priv *priv,
                              u8 reg, const u8 *data, u32 len)
 {
        int ret;
-       u8 buf[len+1];
+       u8 buf[MAX_WRITE_REGSIZE + 1];
        struct i2c_msg msg[1] = {
                {
                        .addr = priv->i2c_address,
                        .flags = 0,
-                       .len = sizeof(buf),
+                       .len = len + 1,
                        .buf = buf,
                }
        };
 
+       if (len + 1 >= sizeof(buf)) {
+               dev_warn(&priv->i2c->dev,"wr reg=%04x: len=%d is too big!\n",
+                        reg, len + 1);
+               return -E2BIG;
+       }
+
        horus3a_i2c_debug(priv, reg, 1, data, len);
        buf[0] = reg;
        memcpy(&buf[1], data, len);