On Mon, Apr 06, 2020 at 10:16:56PM +0800, Yafang Shao wrote:
> On Mon, Apr 6, 2020 at 10:11 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> >
> > On Mon, Apr 06, 2020 at 10:09:55PM +0800, Yafang Shao wrote:
> > > What about ida_alloc_range() ? Should we correct it as well ?
> > >
> > >
> > > * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
> > > * or %-ENOSPC if there are no free IDs.
> > > */
> > > int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max,
> > > gfp_t gfp)
> > >
> > > If there're no free IDs, ida_alloc_range() also returns ENOSPC.
> >
> > Do you want to check all the callers of ida_.*alloc()?
>
> Sorry, I can't your point.
Changing the value returned by ida_alloc_range() would require checking
every caller to see if it would break anything. That's why I didn't
change it when I rewrote it.
> I just find the mem_cgroup_css_alloc() will use ida too.
> mem_cgroup_css_alloc
> memcg_online_kmem
> memcg_alloc_cache_id
> ida_simple_get
>
> I think we should keep the behavior consistent here.
ENOSPC doesn't make much sense here. So I'd do:
id = ida_simple_get(&memcg_cache_ida,
0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
+ if (id == -ENOSPC)
+ return -EBUSY;
if (id < 0)
return id;
