On 2/5/21 2:46 AM, Joao Martins wrote: ...>> If instead you keep npages constant like it naturally wants to be, you could
just do a "(*ntails)++" in the loop, to take care of *ntails.I didn't do it as such as I would need to deref @ntails per iteration, so it felt more efficient to do as above. On a second thought, I could alternatively do the following below, thoughts? diff --git a/mm/gup.c b/mm/gup.c index d68bcb482b11..8defe4f670d5 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -215,6 +215,32 @@ void unpin_user_page(struct page *page) } EXPORT_SYMBOL(unpin_user_page); +static inline void compound_next(unsigned long i, unsigned long npages, + struct page **list, struct page **head, + unsigned int *ntails) +{ + struct page *page; + unsigned int nr; + + if (i >= npages) + return; + + page = compound_head(list[i]); + for (nr = i + 1; nr < npages; nr++) { + if (compound_head(list[nr]) != page) + break; + } + + *head = page; + *ntails = nr - i; +} +
Yes, this is cleaner and quite a bit easier to verify that it is correct.
However, given that the patch is correct and works as-is, the above is really just an optional idea, so please feel free to add: Reviewed-by: John Hubbard <[email protected]>Thanks! Hopefully I can retain that if the snippet above is preferred? Joao
Yes. Still looks good. thanks, -- John Hubbard NVIDIA
