Re: [Qemu-devel] Node deletion in aio_set_fd_handler

[Fam Zheng <famz@redhat.com>]

On Fri, 08/03 08:13, Paolo Bonzini wrote:
> On 03/08/2018 04:42, Fam Zheng wrote:
> > Paolo, is this else branch dead code (or bug?):
> > 
> >         /* If the lock is held, just mark the node as deleted */
> >         if (qemu_lockcnt_count(&ctx->list_lock)) {
> >             node->deleted = 1;
> >             node->pfd.revents = 0;
> >         } else {
> >             /* Otherwise, delete it for real.  We can't just mark it as
> >              * deleted because deleted nodes are only cleaned up while
> >              * no one is walking the handlers list.
> >              */
> >             QLIST_REMOVE(node, node);
> >             deleted = true;
> >         }
> > 
> > Since we are in a qemu_lockcnt_lock/unlock section?
> 
> No, qemu_lockcnt_count returns the number of nested qemu_lockcnt_inc/dec
> (read-side) sections.  lock/unlock is for the write side.
> 
> The comment should be improved (e.g. "if a read is in progress, just
> mark the node as deleted").

Yeah, that explains! Agree about the comment, I'll send a patch then. Thanks.

Fam