Re: [patch 00/26] Xen-paravirt_ops: Xen guest implementation for paravirt_ops interface

Jeremy Fitzhardinge
2007-03-16T19:26:37Z

Christoph Hellwig wrote:
> On Fri, Mar 16, 2007 at 10:26:55AM -0700, Jeremy Fitzhardinge wrote:
>
>> +#ifdef CONFIG_HIGHPTE
>> + .kmap_atomic_pte = native_kmap_atomic_pte,
>> +#else
>> + .kmap_atomic_pte = paravirt_nop,
>> +#endif
>>
>
> This is ifdefing is quite ugly. Shouldn't native_kmap_atomic_pte
> just be a noop in the !CONFIG_HIGHPTE case?
>

Yes, but the trouble is that asm/highmem.h simply isn't included in the
!HIGHMEM case, so I can't put anything in there, and putting anything
pv_ops related into linux/highmem.h isn't appropriate either.

>> -void *kmap_atomic(struct page *page, enum km_type type)
>> +void *_kmap_atomic(struct page *page, enum km_type type, pgprot_t prot)
>>
>
> We normally call our "secial" function __foo, not _foo. But in this
> case it really should have a more meaningfull name like
> kmap_atomic_prot anyway.
>

OK.

>> +void *kmap_atomic(struct page *page, enum km_type type)
>> +{
>> + return _kmap_atomic(page, type, kmap_prot);
>>
>
> And this one should probably be an inline.
>

OK, if you think it makes a difference.

>> +static inline void *native_kmap_atomic_pte(struct page *page, enum km_type type)
>> +{
>> + return kmap_atomic(page, type);
>> +}
>> +
>> +#ifndef CONFIG_PARAVIRT
>> +#define kmap_atomic_pte(page, type) kmap_atomic(page, type)
>> +#endif
>>
>
> This is all getting rather ugly just for your pagetable hackery.
>

Well, I could promote kmap_atomic_pte to a first-class interface, but it
seems like overkill.

J