[PATCH 2/6] treewide: remove using list iterator after loop body as a ptr

[Matthew Wilcox]

On Mon, Feb 28, 2022 at 12:10:24PM -0800, Linus Torvalds wrote:
> We can do
> 
>         typeof(pos) pos
> 
> in the 'for ()' loop, and never use __iter at all.
> 
> That means that inside the for-loop, we use a _different_ 'pos' than outside.

Then we can never use -Wshadow ;-(  I'd love to be able to turn it on;
it catches real bugs.

> +#define list_for_each_entry(pos, head, member)					\
> +	for (typeof(pos) pos = list_first_entry(head, typeof(*pos), member);	\
> +	     !list_entry_is_head(pos, head, member);	\
>  	     pos = list_next_entry(pos, member))