Re: [PATCH 2/6] block: add dio_w_*() wrappers for pin, unpin user pages

[Andrew Morton]

On Sat, 27 Aug 2022 16:59:32 -0700 John Hubbard <jhubbard@xxxxxxxxxx> wrote:

> Anyway, I'll change my patch locally for now, to this:
> 
> static inline void dio_w_unpin_user_pages(struct page **pages,
> 					  unsigned long npages)
> {
> 	/* Careful, release_pages() uses a smaller integer type for npages: */
> 	if (WARN_ON_ONCE(npages > (unsigned long)INT_MAX))
> 		return;
> 
> 	release_pages(pages, (int)npages);
> }

Well, it might be slower.  release_pages() has a ton of fluff.

As mentioned, the above might be faster if the pages tend
to have page_count()==1??