Re: [PATCH 4/8] Arm: prune #include-s needed by domain.h

[Jan Beulich <jbeulich@xxxxxxxx>]

On 17.07.2020 16:44, Julien Grall wrote:
> On 15/07/2020 11:39, Jan Beulich wrote:
>> --- a/xen/include/asm-arm/domain.h
>> +++ b/xen/include/asm-arm/domain.h
>> @@ -2,7 +2,7 @@
>>   #define __ASM_DOMAIN_H__
>>   
>>   #include <xen/cache.h>
>> -#include <xen/sched.h>
>> +#include <xen/timer.h>
>>   #include <asm/page.h>
>>   #include <asm/p2m.h>
>>   #include <asm/vfp.h>
>> @@ -11,8 +11,6 @@
>>   #include <asm/vgic.h>
>>   #include <asm/vpl011.h>
>>   #include <public/hvm/params.h>
>> -#include <xen/serial.h>
> 
> While we don't need the rbtree.h, we technically need serial.h for using 
> vuart_info.

The only reference to it is

        const struct vuart_info     *info;

which doesn't require a definition nor even a forward declaration
of struct vuart_info. It should just be source files instantiating
a struct or de-referencing pointers to one that actually need to
see the full declaration. The only source file doing so (vuart.c)
already includes xen/serial.h. (In fact, it being just a single
source file doing so, the struct definition could [and imo should]
be moved there. The type can be entirely opaque to the rest of the
code base, as - over time - we've been doing for other structs.)

> I would rather prefer if headers are not implicitly included whenever it 
> is possible.

I agree with this principle, where it applies.

Jan