On 03/30/2017 08:18 PM, Matthew Wilcox wrote:
> On Thu, Mar 30, 2017 at 01:27:19PM +0300, Andrey Ryabinin wrote:
>> vfree() can be used in any atomic context and there is no
>> vfree_atomic() callers left, so let's remove it.
>
> We might still get warnings though.
>
>> @@ -1588,9 +1556,11 @@ void vfree(const void *addr)
>>
>> if (!addr)
>> return;
>> - if (unlikely(in_interrupt()))
>> - __vfree_deferred(addr);
>> - else
>> + if (unlikely(in_interrupt())) {
>> + struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
>> + if (llist_add((struct llist_node *)addr, &p->list))
>> + schedule_work(&p->wq);
>> + } else
>> __vunmap(addr, 1);
>> }
>> EXPORT_SYMBOL(vfree);
>
> If I disable preemption, then call vfree(), in_interrupt() will not be
> true (I've only incremented preempt_count()), then __vunmap() calls
> remove_vm_area() which calls might_sleep(), which will warn.
The first patch removed this might_sleep() .
> So I think this check needs to change from in_interrupt() to in_atomic().
>
