Hi Emil,
On 03/08/2018 05:58 AM, Emil Velikov wrote:
Hi Gustavo,
On 7 March 2018 at 19:54, Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> wrote:
In preparation to enabling -Wvla, remove VLA and replace it
with a fixed-length array instead. Also, remove variable 'len'.
What is the reason behind adding -Wvla? Is there a thread some that I
can read up on?
Sure. This is the thread: https://lkml.org/lkml/2018/3/7/621
Notice that no new IDs have been added in seven years.
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/video/fbdev/via/via_aux_vt1632.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/via/via_aux_vt1632.c b/drivers/video/fbdev/via/via_aux_vt1632.c
index d24f4cd..0cd0d2a 100644
--- a/drivers/video/fbdev/via/via_aux_vt1632.c
+++ b/drivers/video/fbdev/via/via_aux_vt1632.c
@@ -35,10 +35,10 @@ static void probe(struct via_aux_bus *bus, u8 addr)
.addr = addr,
.name = name};
/* check vendor id and device id */
- const u8 id[] = {0x06, 0x11, 0x92, 0x31}, len = ARRAY_SIZE(id);
- u8 tmp[len];
+ const u8 id[4] = {0x06, 0x11, 0x92, 0x31};
+ u8 tmp[4];
- if (!via_aux_read(&drv, 0x00, tmp, len) || memcmp(id, tmp, len))
+ if (!via_aux_read(&drv, 0x00, tmp, 4) || memcmp(id, tmp, 4))
Generally, hard coding a bunch of numbers like that makes for
confusing and fragile code.
You are correct.
A lot simpler and more obvious solution is like the following.
It silences the compiler warning (-Wvla - pedantic) you while keeping
the original clarity.
const u8 id[] = {0x06, 0x11, 0x92, 0x31}, len = ARRAY_SIZE(id);
- u8 tmp[len];
+ u8 tmp[ARRAY_SIZE(id)]; // Using len causes a Wvla warning
Yeah, this works just fine.
There are a total of four instances of this same issue in other files
for the VIA component. I'll fix them and send a single patch shortly.
Thanks for the feedback.
I appreciate it.
--
Gustavo
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