On Sat, 18 Apr 2020 14:34:51 -0700 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> On Sat, Apr 18, 2020 at 01:15:09PM -0700, Andrew Morton wrote:
> > > --- a/ipc/util.c
> > > +++ b/ipc/util.c
> > > @@ -104,12 +104,20 @@ static const struct rhashtable_params ipc_kht_params = {
> > > .automatic_shrinking = true,
> > > };
> > >
> > > +#ifdef CONFIG_CHECKPOINT_RESTORE
> >
> > The code grew a few additional CONFIG_CHECKPOINT_RESTORE ifdefs.
> > What's going on here? Why is CRIU special in ipc/?
>
> "grew a few"? I added (this) one and deleted two others. From in the
> middle of functions, like we usually prefer.
>
Oh.
>
> @@ -17,11 +17,11 @@ struct ipc_ids {
> ...
> #ifdef CONFIG_CHECKPOINT_RESTORE
> - int next_id;
> + int restore_id;
> #endif
>
> > > +#define set_restore_id(ids, x) ids->restore_id = x
> > > +#define get_restore_id(ids) ids->restore_id
> > > +#else
> > > +#define set_restore_id(ids, x) do { } while (0)
> > > +#define get_restore_id(ids) (-1)
> > > +#endif
> >
> > Well these are ugly. Can't all this be done in C?
>
> Would you rather see it done as:
>
> static inline void set_restore_id(struct ipc_ids *ids, int id)
> {
> #ifdef CONFIG_CHECKPOINT_RESTORE
> ids->restore_id = id;
> #endif
> }
>
> static inline int get_restore_id(struct ipc_ids *ids)
> {
> #ifdef CONFIG_CHECKPOINT_RESTORE
> return ids->restore_id;
> #else
> return -1;
> #endif
> }
Looks nicer. Has type checking regardless of Kconfig. Doesn't have
lval-and-rval in one case, neither in the other. Doesn't risk
unused-var warnings dependent on Kconfig. Etc.
Could also do
#ifdef CONFIG_CHECKPOINT_RESTORE
static inline void set_restore_id(struct ipc_ids *ids, int id)
{
ids->restore_id = id;
}
static inline int get_restore_id(struct ipc_ids *ids)
{
return ids->restore_id;
return -1;
}
#else
...
