On 28 June 2018 at 11:25, Peter Zijlstra <pet...@infradead.org> wrote: > On Thu, Jun 28, 2018 at 11:04:45AM +0200, Ard Biesheuvel wrote: >> On 28 June 2018 at 11:02, Ard Biesheuvel <ard.biesheu...@linaro.org> wrote: >> >>> @@ -56,7 +72,9 @@ jump_label_sort_entries(struct jump_entry *start, >> >>> struct jump_entry *stop) >> >>> >> >>> size = (((unsigned long)stop - (unsigned long)start) >> >>> / sizeof(struct jump_entry)); >> >>> - sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); >> >>> + sort(start, size, sizeof(struct jump_entry), jump_label_cmp, >> >>> + IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE) ? >> >>> jump_label_swap >> >>> + : NULL); >> >>> } >> >> >> >> That will result in jump_label_swap being an unused symbol for some >> >> compile options. >> > >> > No, and isn't that the point of IS_ENABLED()? The compiler sees a >> > reference to jump_label_swap(), so it won't complain about it being >> > unused. > > Ah, ok. I hadn't figured it was quite that smart about it. >
Yeah. I could use a temp variable to make the indentation less obnoxious, but since this is an opt-in feature, I'd like to preserve the NULL (*swap)() argument for the existing users. >> > Meh. I thought IS_ENABLED() was preferred over #ifdef, no? > > Dunno, I just reacted to the proposed code's uglyness :-) > I will try to come up with something that rhymes, ok? :-) >> ... and it means the sort() routine will unconditionally perform an >> indirect function call even if the arch does not require it. > > Yeah, not sure I care about that here, this is a one time affair, very > far away from any fast paths. > Fair enough.
