Re: [PATCH] staging: wfx: add gcc extension __force cast

From: Al Viro
Date: Sat Nov 09 2019 - 04:19:49 EST


On Fri, Nov 08, 2019 at 11:38:37PM +0000, Jules Irenge wrote:
> Add gcc extension __force and __le32 cast to fix warning issued by Sparse tool."warning: cast to restricted __le32"
>
> Signed-off-by: Jules Irenge <jbi.octave@xxxxxxxxx>
> ---
> drivers/staging/wfx/debug.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/wfx/debug.c b/drivers/staging/wfx/debug.c
> index 0a9ca109039c..aa7b2dd691b9 100644
> --- a/drivers/staging/wfx/debug.c
> +++ b/drivers/staging/wfx/debug.c
> @@ -72,7 +72,7 @@ static int wfx_counters_show(struct seq_file *seq, void *v)
> return -EIO;
>
> #define PUT_COUNTER(name) \
> - seq_printf(seq, "%24s %d\n", #name ":", le32_to_cpu(counters.count_##name))
> + seq_printf(seq, "%24s %d\n", #name ":", le32_to_cpu((__force __le32)(counters.count_##name)))

NAK. force-cast (and it's not a gcc extension, BTW - it's sparse) is basically
"I know better; the code is right, so STFU already". *IF* counters.count_...
is really little-endian 32bit, then why isn't it declared that way? And if
it's host-endian, you've just papered over a real bug here.

As a general rule "fix" doesn't mean "tell it to shut up"...