Re: [Qemu-devel] [PATCH 4/4] linux-aio: simplify removal of completed iocbs from the list

[Kevin Wolf]

Am 11.12.2014 um 14:15 hat Paolo Bonzini geschrieben:
> 
> 
> On 11/12/2014 14:13, Kevin Wolf wrote:
> >> > +#define QSIMPLEQ_SPLIT_AFTER(head1, head2, elm, field) do {             
> >> > \
> >> > +    if (((head1)->sqh_first = (head2)->sqh_first) == NULL) {            
> >> > \
> >> > +        (head1)->sqh_last = &(head1)->sqh_first;                        
> >> > \
> >> > +    } else {                                                            
> >> > \
> >> > +        (head1)->sqh_last = &(elm)->field.sqe_next;                     
> >> > \
> >> > +        if (((head2)->sqh_first = (elm)->field.sqe_next) == NULL) {     
> >> > \
> >> > +            (head2)->sqh_last = &(head2)->sqh_first;                    
> >> > \
> >> > +        }                                                               
> >> > \
> >> > +    }                                                                   
> >> > \
> >> > +} while (/*CONSTCOND*/0)
> > Wouldn't it be easier to write a macro that doesn't split a queue in
> > two, but simply removes everything up to a given element?
> 
> Yeah, though I figured that in the common case you'd have to free those
> elements or otherwise process them.  But I left this patch last because
> I wasn't sure about the API.  Feel free to ignore it, also given the
> above comment about EAGAIN.

I actually like the idea of this patch.

> > Anyway, if you really want to implement a split operation, I think you
> > also need to break the actual chain, i.e. (head1)->sqh_last.sqe_next =
> > NULL.

Can you please fix this one and send a v2?

The EAGAIN thing doesn't need to be fixed because it's ignored anyway. A
cleanup is unrelated and can be done later. As for the abort() in patch
2, I'll leave the decision to you.

Overall it looks like a nice series.

Kevin