Re: [PATCH v2 03/21] migration: remove unreachble RDMA code in save_hook impl

[Juan Quintela <quintela@redhat.com>]

Daniel P. Berrangé <berrange@redhat.com> wrote:
> The QEMUFile 'save_hook' callback has a 'size_t size' parameter.
>
> The RDMA impl of this has logic that takes different actions
> depending on whether the value is zero or non-zero. It has
> commented out logic that would have taken further actions
> if the value was negative.
>
> The only place where the 'save_hook' callback is invoked is
> the ram_control_save_page() method, which passes 'size'
> through from its caller. The only caller of this method is
> in turn control_save_page(). This method unconditionally
> passes the 'TARGET_PAGE_SIZE' constant for the 'size' parameter.
>
> IOW, the only scenario for 'size' that can execute in the
> qemu_rdma_save_page method is 'size > 0'. The remaining code
> has been unreachable since RDMA support was first introduced
> 9 years ago.
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

You missed this call:

@@ -1571,18 +1547,6 @@ static uint64_t qemu_rdma_poll(RDMAContext *rdma, struct ibv_cq *cq,
         if (rdma->nb_sent > 0) {
             rdma->nb_sent--;
         }
-
-        if (!rdma->pin_all) {
-            /*
-             * FYI: If one wanted to signal a specific chunk to be unregistered
-             * using LRU or workload-specific information, this is the function
-             * you would call to do so. That chunk would then get asynchronously
-             * unregistered later.
-             */
-#ifdef RDMA_UNREGISTRATION_EXAMPLE
-            qemu_rdma_signal_unregister(rdma, index, chunk, wc.wr_id);
-#endif
-        }

But as RDMA_UNREGISTRATION_EXAMPLE has never been set, I am sending a
separate patch to remove it.

Later, Juan.