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).
