On Wed, Sep 04, 2024 at 05:49:15PM +0200, Vlastimil Babka wrote:
> On 9/4/24 17:16, Mike Rapoport wrote:
> > On Tue, Sep 03, 2024 at 04:20:43PM +0200, Christian Brauner wrote:
> >> @@ -275,7 +285,7 @@ do_kmem_cache_create_usercopy(const char *name,
> >>
> >> mutex_lock(&slab_mutex);
> >>
> >> - err = kmem_cache_sanity_check(name, size);
> >> + err = kmem_cache_sanity_check(name, object_size);
> >> if (err) {
> >> goto out_unlock;
> >> }
> >> @@ -296,12 +306,14 @@ do_kmem_cache_create_usercopy(const char *name,
> >>
> >> /* Fail closed on bad usersize of useroffset values. */
> >> if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
> >> - WARN_ON(!usersize && useroffset) ||
> >> - WARN_ON(size < usersize || size - usersize < useroffset))
> >> - usersize = useroffset = 0;
> >> -
> >> - if (!usersize)
> >> - s = __kmem_cache_alias(name, size, align, flags, ctor);
> >> + WARN_ON(!args->usersize && args->useroffset) ||
> >> + WARN_ON(object_size < args->usersize ||
> >> + object_size - args->usersize < args->useroffset))
> >> + args->usersize = args->useroffset = 0;
> >> +
> >> + if (!args->usersize)
> >> + s = __kmem_cache_alias(name, object_size, args->align, flags,
> >> + args->ctor);
> >
> > Sorry I missed it in the previous review, but nothing guaranties that
> > nobody will call kmem_cache_create_args with args != NULL.
> >
> > I think there should be a check for args != NULL and a substitution of args
> > with defaults if it actually was NULL.
>
> Hm there might be a bigger problem with this? If we wanted to do a
> (non-flag-day) conversion to the new kmem_cache_create() for some callers
> that need none of the extra args, passing NULL wouldn't work for the
> _Generic((__args) looking for "struct kmem_cache_args *" as NULL is not of
> that type, right?
>
> I tried and it really errors out.
How about
#define kmem_cache_create(__name, __object_size, __args, ...) \
_Generic((__args), \
struct kmem_cache_args *: __kmem_cache_create_args, \
void *: __kmem_cache_create_args, \
default: __kmem_cache_create)(__name, __object_size, __args, __VA_ARGS__)
--
Sincerely yours,
Mike.
