Re: [PATCH drm-next v2 03/16] maple_tree: split up MA_STATE() macro

Matthew Wilcox
2023-02-17T19:45:52Z

On Fri, Feb 17, 2023 at 02:44:09PM +0100, Danilo Krummrich wrote:
> \#define SAMPLE_ITER(name, __mgr) \
> struct sample_iter name = { \
> .mas = __MA_STATE(&(__mgr)->mt, 0, 0),

This is usually called MA_STATE_INIT()

> #define sample_iter_for_each_range(it__, start__, end__) \
> for ((it__).mas.index = start__, (it__).entry = mas_find(&(it__).mas, end__ - 1); \
> (it__).entry; (it__).entry = mas_find(&(it__).mas, end__ - 1))

This is a bad iterator design. It's usually best to do this:

struct sample *sample;
SAMPLE_ITERATOR(si, min);

sample_iter_for_each(&si, sample, max) {
frob(mgr, sample);
}

I don't mind splitting apart MA_STATE_INIT from MA_STATE, and if you
do that, we can also use it in VMA_ITERATOR.