[PATCH] media: rc: iguanair: Replace zero-length array with flexible-array member

From: Gustavo A. R. Silva
Date: Tue Feb 11 2020 - 15:43:17 EST


The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/media/rc/iguanair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/rc/iguanair.c b/drivers/media/rc/iguanair.c
index fbacb13b614b..028374b04e47 100644
--- a/drivers/media/rc/iguanair.c
+++ b/drivers/media/rc/iguanair.c
@@ -85,7 +85,7 @@ struct send_packet {
uint8_t channels;
uint8_t busy7;
uint8_t busy4;
- uint8_t payload[0];
+ uint8_t payload[];
};

static void process_ir_data(struct iguanair *ir, unsigned len)
--
2.25.0