Re: drm pull for v5.3-rc1

[Christoph Hellwig <hch@infradead.org>]

On Tue, Aug 06, 2019 at 12:09:38PM -0700, Matthew Wilcox wrote:
> Has anyone looked at turning the interface inside-out?  ie something like:
> 
> 	struct mm_walk_state state = { .mm = mm, .start = start, .end = end, };
> 
> 	for_each_page_range(&state, page) {
> 		... do something with page ...
> 	}
> 
> with appropriate macrology along the lines of:
> 
> #define for_each_page_range(state, page)				\
> 	while ((page = page_range_walk_next(state)))
> 
> Then you don't need to package anything up into structs that are shared
> between the caller and the iterated function.

I'm not an all that huge fan of super magic macro loops.  But in this
case I don't see how it could even work, as we get special callbacks
for huge pages and holes, and people are trying to add a few more ops
as well.