On 03.12.20 16:29, Jan Beulich wrote:
> On 03.12.2020 16:14, Jürgen Groß wrote:
>> On 03.12.20 15:59, Jan Beulich wrote:
>>> On 01.12.2020 09:21, Juergen Gross wrote:
>>>> @@ -100,11 +112,58 @@ static void hypfs_unlock(void)
>>>>        }
>>>>    }
>>>>    
>>>> +const struct hypfs_entry *hypfs_node_enter(const struct hypfs_entry *entry)
>>>> +{
>>>> +    return entry;
>>>> +}
>>>> +
>>>> +void hypfs_node_exit(const struct hypfs_entry *entry)
>>>> +{
>>>> +}
>>>> +
>>>> +static int node_enter(const struct hypfs_entry *entry)
>>>> +{
>>>> +    const struct hypfs_entry **last = &this_cpu(hypfs_last_node_entered);
>>>> +
>>>> +    entry = entry->funcs->enter(entry);
>>>> +    if ( IS_ERR(entry) )
>>>> +        return PTR_ERR(entry);
>>>> +
>>>> +    ASSERT(!*last || *last == entry->parent);
>>>> +
>>>> +    *last = entry;
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static void node_exit(const struct hypfs_entry *entry)
>>>> +{
>>>> +    const struct hypfs_entry **last = &this_cpu(hypfs_last_node_entered);
>>>> +
>>>> +    if ( !*last )
>>>> +        return;
>>>
>>> Under what conditions is this legitimate to happen? IOW shouldn't
>>> there be an ASSERT_UNREACHABLE() here?
>>
>> This is for the "/" node.
> 
> I.e. would ASSERT(!entry->parent) be appropriate to add here, at
> the same time serving as documentation of what you've just said?

I rechecked and have found that this was a remnant from an earlier
variant. *last won't ever be NULL, so the if can be dropped (a NULL
will be catched by the following ASSERT()).


Juergen