Re: [PATCH 36/51] writeback: implement bdi_for_each_wb()

[Tejun Heo]

On Wed, Jul 01, 2015 at 09:27:57AM +0200, Jan Kara wrote:
> > +#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id)		\
> > +	for ((iter)->next_id = (start_blkcg_id);			\
> > +	     ({	(wb_cur) = !(iter)->next_id++ ? &(bdi)->wb : NULL; }); )
> > +
> 
> This looks quite confusing. Won't it be easier to understand as:
> 
> struct wb_iter {
> } __attribute__ ((unused));
> 
> #define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \
>   if (((wb_cur) = (!start_blkcg_id ? &(bdi)->wb : NULL)))

But then break or continue wouldn't work as expected.  It can get
really confusing when it's wrapped by an outer loop.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/