Re: [RFC PATCH] cleanup: make scoped_guard() to be return-friendly

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 9/30/24 13:30, Markus Elfring wrote:
> …
>> Current scoped_guard() implementation does not support that,
>> due to compiler complaining:
> …
>> +++ b/include/linux/cleanup.h
>> @@ -168,9 +168,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \
>>
>>   #define __guard_ptr(_name) class_##_name##_lock_ptr
>>
>> -#define scoped_guard(_name, args...)					\
>> -	for (CLASS(_name, scope)(args),					\
>> -	     *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1)
>> +#define scoped_guard(_name, args...)	\
>> +	__scoped_guard_labeled(__UNIQUE_ID(label), _name, args)
>> +
>> +#define __scoped_guard_labeled(_label, _name, args...)	\
>> +	if (0)						\
>> +		_label: ;				\
>> +	else						\
>> +		for (CLASS(_name, scope)(args);		\
>> +		     __guard_ptr(_name)(&scope), 1;	\
>> +		     ({ goto _label; }))
>>
>>   #define scoped_cond_guard(_name, _fail, args...) \
>>   	for (CLASS(_name, scope)(args), \
> 
> * How do you think about to define such macros before their use?

will do, no problem

> 
> * Would you ever like to avoid reserved identifiers in such source code?
>    https://wiki.sei.cmu.edu/confluence/display/c/DCL37-C.+Do+not+declare+or+define+a+reserved+identifier

we already don't care about this guideline (see __guard_ptr())

OTOH there is DCL37-C-EX3 that says "does not apply for std lib",
and here (in the kernel) we don' need stdlib, (or for the purpose of
bureaucracy we ARE the stdlib for ourselves)

> 
> 
> Regards,
> Markus