On Thu 19-12-13 13:26:12, Vasily Averin wrote: > On 12/19/2013 12:39 PM, Vladimir Davydov wrote: > > On 12/19/2013 12:17 PM, Vasily Averin wrote: > >> On 12/18/2013 05:16 PM, Vladimir Davydov wrote: > >>> --- a/mm/slab_common.c > >>> +++ b/mm/slab_common.c > >>> @@ -176,8 +176,9 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, > >>> get_online_cpus(); > >>> mutex_lock(&slab_mutex); > >>> > >>> - if (!kmem_cache_sanity_check(memcg, name, size) == 0) > >>> - goto out_locked; > >>> + err = kmem_cache_sanity_check(memcg, name, size); > >>> + if (err) > >>> + goto out_unlock; > >>> > >>> /* > >>> * Some allocators will constraint the set of valid flags to a subset > >> Theoretically in future kmem_cache_sanity_check() can return positive value. > >> Probably it's better to check (err < 0) in caller ? > > > > Hmm, why? What information could positive retval carry here? We have > > plenty of places throughout the code where we check for (err), not > > (err<0), simply because it looks clearer, e.g. look at > > __kmem_cache_create() calls. If it returns a positive value one day, we > > will have to parse every place where it's called. Anyway, if someone > > wants to change a function behavior, he must check every place where > > this function is called and fix them accordingly. > > I believe expected semantic of function -- return negative in case of error. > So correct error cheek should be (err < 0). > (err) check is semantically incorrect, and it can lead to troubles in future. No, this function returns -ERRNO or 0 on success. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>