On 1 Apr 2022, at 15:01, Linus Torvalds wrote:
> On Fri, Apr 1, 2022 at 11:56 AM Zi Yan <ziy@xxxxxxxxxx> wrote:
>>
>> How about the patch below? If it looks good, I will send v3.
>
> I can't see anything worrisome, but by now I've looked at several
> versions and who knows what I'm missing.
>
> Making it inline and allowing a NULL 'buddy_pfn' pointer for the cases
> that don't care might be an option, but I don't think it matters
> hugely.
What do you mean by inlining it? Moving the function and __find_buddy_pfn()
to mm/internal.h and mark both inline?
Something like below to allow a NULL 'buddy_pfn'? buddy_pfn is needed
to store the result of __find_buddy_pfn(). The code does not look
as nice as before.
struct page *find_buddy_page_pfn(struct page *page, unsigned long pfn,
unsigned int order, unsigned long *buddy_pfn)
{
struct page *buddy;
if (buddy_pfn) {
*buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (*buddy_pfn - pfn);
} else
buddy = page + (__find_buddy_pfn(pfn, order) - pfn);
if (page_is_buddy(page, buddy, order))
return buddy;
return NULL;
}
or
struct page *find_buddy_page_pfn(struct page *page, unsigned long pfn,
unsigned int order, unsigned long *buddy_pfn)
{
struct page *buddy;
unsigned long local_buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (local_buddy_pfn - pfn);
if (buddy_pfn)
*buddy_pfn = local_buddy_pfn;
if (page_is_buddy(page, buddy, order))
return buddy;
return NULL;
}
--
Best Regards,
Yan, Zi
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