Re: [PATCH 2/2][RESEND] tracing: Shrink the size of struct ftrace_event_field

[Li Zefan]

>> @@ -111,6 +111,11 @@ static int __trace_define_field(struct list_head *head, const char *type,
>>  	field->size = size;
>>  	field->is_signed = is_signed;
> 
> I think we should just change is_signed to bool. At least the parameter.
> Or we can make the assignment: field->is_signed = !!is_signed; and nuke
> the check below.
> 

Changing field->is_signed to bool won't shrink the size of the struct.
I prefer: field->is_signed = !!is_signed.

>>  
>> +	WARN_ON(offset >= (1 << 12));
>> +	WARN_ON(size >= (1 << 12));
>> +	WARN_ON(is_signed >= (1 << 1));
>> +	WARN_ON(field->filter_type >= (1 << 4));
> 
> Note, the test for field->filter_type is wrong.
> 

oops.

> We should make a helper macro:
> 
> #define VERIFY_SIZE(type) WARN_ON(type > field->type)
> 

Much better!

> and then have:
> 
> 	VERIFY_SIZE(offset);
> 	VERIFY_SIZE(size);
> 	VERIFY_SIZE(filter_type);

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