On Tue, 12 Dec 2023 20:57:48 +0000 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> On Tue, Dec 12, 2023 at 11:46:40AM -0800, Sidhartha Kumar wrote:
> > + /* Slot store, does not require additional nodes */
> > + if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
> > + || (wr_mas.offset_end - mas->offset == 1)))
> > + return 0;
>
> Should we refactor this into a mas_is_slot_store() predicate?
>
> A few coding-style problems with it as it's currently written:
>
> 1. The indentation on the second line is wrong. It makes the
> continuation of the condition look like part of the statement. Use
> extra whitespace to indent. eg:
>
> if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
> || (wr_mas.offset_end - mas->offset == 1)))
> return 0;
>
> 2. The operator goes last on the line, not at the beginning of the
> continuation line. ie:
>
> if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree)) ||
> (wr_mas.offset_end - mas->offset == 1)))
> return 0;
>
> 3. You don't need parens around the !mt_in_rcu(mas->tree). There's
> no ambiguity to solve here:
>
> if ((node_size == mas->end) && (!mt_in_rcu(mas->tree) ||
> (wr_mas.offset_end - mas->offset == 1)))
> return 0;
>
> But I'd write it as:
>
> if ((node_size == mas->end) &&
> (!mt_in_rcu(mas->tree) || (wr_mas.offset_end - mas->offset == 1)))
> return 0;
>
> because then the whitespace matches how you're supposed to parse the
> condition, and so the next person to read this code will have an easier
> time of it.
Yup. But I'd suggest going further:
/* Slot store, does not require additional nodes */
if (node_size == mas->end) {
/* comment goes here */
if (!mt_in_rcu(mas->tree))
return 0;
/* and here too */
if (wr_mas.offset_end - mas->offset == 1)
return 0;
}
ie: create space to add those comments explaining the reason for each test.
