On Mon, Jul 24, 2023 at 1:41 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Mon, Jul 24, 2023, at 21:15, Alexei Starovoitov wrote: > > On Mon, Jul 24, 2023 at 11:30 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > >> On Mon, Jul 24, 2023, at 20:13, Arnd Bergmann wrote: > >> > >> I have a minimized test case at https://godbolt.org/z/hK4ev17fv > >> that shows the problem happening with all versions of gcc > >> (4.1 through 14.0) if I force the dec_active() function to be > >> inline and force inc_active() to be non-inline. > > > > That's a bit of cheating, but I see your point now. > > How about we do: > > diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c > > index 51d6389e5152..3fa0944cb975 100644 > > --- a/kernel/bpf/memalloc.c > > +++ b/kernel/bpf/memalloc.c > > @@ -183,11 +183,11 @@ static void inc_active(struct bpf_mem_cache *c, > > unsigned long *flags) > > WARN_ON_ONCE(local_inc_return(&c->active) != 1); > > } > > > > -static void dec_active(struct bpf_mem_cache *c, unsigned long flags) > > +static void dec_active(struct bpf_mem_cache *c, unsigned long *flags) > > { > > local_dec(&c->active); > > if (IS_ENABLED(CONFIG_PREEMPT_RT)) > > - local_irq_restore(flags); > > + local_irq_restore(*flags); > > } > > > Sure, that's fine. Between this and the two suggestions I had > (__always_inline or passing the flags from inc_active as a > return code), I don't have a strong preference, so pick whichever > you like. I think: static void dec_active(struct bpf_mem_cache *c, unsigned long *flags) is cleaner. Could you send a patch?
