Re: [PATCH 1/2] migration/rdma: honor blocking mode in QIOChannelRDMA readv

[Bin Guo <guobin@linux.alibaba.com>]

On Tue, 16 Jun 2026, Peter Xu wrote:
> this patch made it the other way round: the channel didn't respect
> blocking mode because it always blocks, not always non-block.

You're right, the commit message was misleading.

The function already blocks inside qemu_rdma_exchange_recv() when
waiting for the next RDMA SEND message.  What it didn't do was keep
blocking when the bytes from a *single* receive were not enough to
satisfy the full request -- it would return partial data instead of
waiting for more.

In blocking mode a QIOChannel readv should keep trying until the
request is satisfied (or an error occurs), matching the behaviour of
other QIOChannel implementations.  That's what the loop is for.

> Also, this is only the read path; there's also write.

The write path already loops over the full iov in
qio_channel_rdma_writev(), so it handles the blocking case
correctly.  Only read needed fixing.

I'll send a v2 with a corrected commit message.  Thanks for the
review.

Bin Guo