[PATCH] nvme-rdma: Fix early queue flags settings

[swise@opengridcomputing.com (Steve Wise)]

> >
> > I can modify the change log, Christoph do you still want a
> > comment in the code?
> 
> Honestly there more I look into this the less I'm happy with the patch.
> queue->flags is an atomic, and as the patch shows we can get
> nvme_rdma_init_queue caled on a queue that still has visibility in
> other threads  So I think we really should not even do that simple
> queue->flags = 0 assignment at all.  We'll need to use clear_bit to
> atomically clear anything that might be set, and we need to be careful
> where we do that.  I think this whole situation that we can get an
> *_init_* function called on something that already is live and visible
> to other threads need to be well documented at least because it's just
> waiting for sucker like me that don't expect that.


Sagi, you originally proposed this in a patch for debugging the crash where
a request is accessing a queue with rdma resources freed:

@@ -542,11 +542,12 @@ static int nvme_rdma_create_queue_ib(struct 
nvme_rdma_queue *queue,
                 goto out_destroy_qp;
         }
         set_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &queue->flags);
+       clear_bit(NVME_RDMA_Q_DELETING, &queue->flags);

         return 0;


Perhaps this is how we should proceed?