On Sat, 2023-12-16 at 14:45 -0300, Marcelo Schmitt wrote:
> Checkpatch presumes attributes marked with __aligned(alignment) are part
> of a function declaration and throws a warning stating that those
> compiler attributes should have an identifier name which is not correct.
> Add __aligned compiler attributes to the list of attribute notes
> so they don't cause warnings anymore.
>
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
> ---
> Any expression that evaluates to an integer that is a power of 2 can be
> within __aligned parenthesis.
> I can't see how we could use a regex to check code meets such constraint (if possible).
You can't because if a #define is used for the alignment
value it is not necessarily available to a patch fragment
or even a file if the #define is in an #include.
> Some additional exotic uses of __aligned are:
> drivers/net/wireless/quantenna/qtnfmac/bus.h:72: char bus_priv[] __aligned(sizeof(void *));
> include/linux/netdevice.h:225:} __aligned(4 * sizeof(unsigned long));
Right, then there are random uses like:
drivers/firmware/qcom/qcom_qseecom_uefisecapp.c: size_t __aligned; \
drivers/firmware/qcom/qcom_qseecom_uefisecapp.c: *__offset = __aligned; \
so there's always some false positive/negative issue
with checkpatch.
Anyway:
Acked-by: Joe Perches <joe@xxxxxxxxxxx>
>
> The regex
> __aligned\s*\(.*\)
> seems to match all use cases.
>
> We might not catch invalid arguments to __aligned, but it looks like making
> checkpath confidently report those wouldn't be feasible anyway.
>
> The patch that would trigger the mentioned warning in now
> patch number 13 (iio: adc: Add support for AD7091R-8).
>
> scripts/checkpatch.pl | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 25fdb7fda112..d56c98146da3 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -512,6 +512,7 @@ our $Attribute = qr{
> __ro_after_init|
> __kprobes|
> $InitAttribute|
> + __aligned\s*\(.*\)|
> ____cacheline_aligned|
> ____cacheline_aligned_in_smp|
> ____cacheline_internodealigned_in_smp|
