Re: [PATCHv11 2/4] gnttab: introduce maptrack lock

[David Vrabel <david.vrabel@citrix.com>]

On 05/06/15 14:35, Jan Beulich wrote:
>>>> On 02.06.15 at 18:26, <david.vrabel@citrix.com> wrote:
>> --- a/xen/common/grant_table.c
>> +++ b/xen/common/grant_table.c
>> @@ -288,10 +288,10 @@ static inline void put_maptrack_handle(
>>      struct grant_table *t, int handle)
>>  {
>> -    spin_lock(&t->lock);
>> +    spin_lock(&t->maptrack_lock);
>>      maptrack_entry(t, handle).ref = t->maptrack_head;
>>      t->maptrack_head = handle;
>> -    spin_unlock(&t->lock);
>> +    spin_unlock(&t->maptrack_lock);
> 
> Starting with this change it becomes unclear what protects the
> maptrack entries - the grant table lock or the maptrack one?

The grant table lock.  The docs aren't very good here -- the maptrack
lock is only for the maptrack free list.

David