On 6/11/25 16:20, Stefano Garzarella wrote:
> On Fri, Jun 06, 2025 at 09:51:29AM +0200, Michal Luczaj wrote:
>> On 6/5/25 12:46, Stefano Garzarella wrote:
>>> On Wed, Jun 04, 2025 at 09:10:19PM +0200, Michal Luczaj wrote:
>>>> On 6/4/25 11:07, Stefano Garzarella wrote:
>>>>> On Wed, May 28, 2025 at 10:44:42PM +0200, Michal Luczaj wrote:
>>>>>> +static int __get_transports(void)
>>>>>> +{
>>>>>> + /* Order must match transports defined in util.h.
>>>>>> + * man nm: "d" The symbol is in the initialized data section.
>>>>>> + */
>>>>>> + const char * const syms[] = {
>>>>>> + "d loopback_transport",
>>>>>> + "d virtio_transport",
>>>>>> + "d vhost_transport",
>>>>>> + "d vmci_transport",
>>>>>> + "d hvs_transport",
>>>>>> + };
>>>>>
>>>>> I would move this array (or a macro that define it), near the transport
>>>>> defined in util.h, so they are near and we can easily update/review
>>>>> changes.
>>>>>
>>>>> BTW what about adding static asserts to check we are aligned?
>>>>
>>>> Something like
>>>>
>>>> #define KNOWN_TRANSPORTS \
>>>
>>> What about KNOWN_TRANSPORTS(_) ?
>>
>> Ah, yeah.
>>
>>>> _(LOOPBACK, "loopback") \
>>>> _(VIRTIO, "virtio") \
>>>> _(VHOST, "vhost") \
>>>> _(VMCI, "vmci") \
>>>> _(HYPERV, "hvs")
>>>>
>>>> enum transport {
>>>> TRANSPORT_COUNTER_BASE = __COUNTER__ + 1,
>>>> #define _(name, symbol) \
>>>> TRANSPORT_##name = _BITUL(__COUNTER__ - TRANSPORT_COUNTER_BASE),
>>>> KNOWN_TRANSPORTS
>>>> TRANSPORT_NUM = __COUNTER__ - TRANSPORT_COUNTER_BASE,
>>>> #undef _
>>>> };
>>>>
>>>> static char * const transport_ksyms[] = {
>>>> #define _(name, symbol) "d " symbol "_transport",
>>>> KNOWN_TRANSPORTS
>>>> #undef _
>>>> };
>>>>
>>>> static_assert(ARRAY_SIZE(transport_ksyms) == TRANSPORT_NUM);
>>>>
>>>> ?
>>>
>>> Yep, this is even better, thanks :-)
>>
>> Although checkpatch complains:
>>
>> ERROR: Macros with complex values should be enclosed in parentheses
>> #105: FILE: tools/testing/vsock/util.h:11:
>> +#define KNOWN_TRANSPORTS(_) \
>> + _(LOOPBACK, "loopback") \
>> + _(VIRTIO, "virtio") \
>> + _(VHOST, "vhost") \
>> + _(VMCI, "vmci") \
>> + _(HYPERV, "hvs")
>>
>> BUT SEE:
>>
>> do {} while (0) advice is over-stated in a few situations:
>>
>> The more obvious case is macros, like MODULE_PARM_DESC, invoked at
>> file-scope, where C disallows code (it must be in functions). See
>> $exceptions if you have one to add by name.
>>
>> More troublesome is declarative macros used at top of new scope,
>> like DECLARE_PER_CPU. These might just compile with a do-while-0
>> wrapper, but would be incorrect. Most of these are handled by
>> detecting struct,union,etc declaration primitives in $exceptions.
>>
>> Theres also macros called inside an if (block), which "return" an
>> expression. These cannot do-while, and need a ({}) wrapper.
>>
>> Enjoy this qualification while we work to improve our heuristics.
>>
>> ERROR: Macros with complex values should be enclosed in parentheses
>> #114: FILE: tools/testing/vsock/util.h:20:
>> + #define _(name, symbol) \
>> + TRANSPORT_##name = BIT(__COUNTER__ - TRANSPORT_COUNTER_BASE),
>>
>> WARNING: Argument 'symbol' is not used in function-like macro
>> #114: FILE: tools/testing/vsock/util.h:20:
>> + #define _(name, symbol) \
>> + TRANSPORT_##name = BIT(__COUNTER__ - TRANSPORT_COUNTER_BASE),
>>
>> WARNING: Argument 'name' is not used in function-like macro
>> #122: FILE: tools/testing/vsock/util.h:28:
>> + #define _(name, symbol) "d " symbol "_transport",
>>
>> Is it ok to ignore this? FWIW, I see the same ERRORs due to similarly used
>> preprocessor directives in fs/bcachefs/alloc_background_format.h, and the
>> same WARNINGs about unused macro arguments in arch/x86/include/asm/asm.h
>> (e.g. __ASM_SEL).
>
> It's just test, so I think it's fine to ignore, but please exaplain it
> in the commit description with also references to other ERRORs/WARNINGs
> like you did here. Let's see what net maintainers think.
Sure, I've added a note. I've also switched the magic macro name '_' to
'x', this seems to be more common.
https://lore.kernel.org/netdev/20250611-vsock-test-inc-cov-v3-0-5834060d9c20@xxxxxxx/
Thanks,
Michal
