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Date:   Sat, 24 Oct 2020 09:36:21 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     zhenwei pi <pizhenwei@bytedance.com>, kbusch@kernel.org,
        hch@lst.de, axboe@fb.com, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] nvme-rdma: handle nvme completion data length
Message-ID: <20201024073621.GA28151@lst.de>
References: <20201023065910.1358586-1-pizhenwei@bytedance.com> <d23e33e7-d545-2ad0-d163-5182dd5430b1@grimberg.me>
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On Fri, Oct 23, 2020 at 11:01:40AM -0700, Sagi Grimberg wrote:
>>   +	/* received data length checking */
>> +	if (unlikely(wc->byte_len < len)) {
>> +		/* zero bytes message could be ignored */
>> +		if (!wc->byte_len) {
>> +			nvme_rdma_post_recv(queue, qe);
>> +			return;
>> +		}
>
> Nothing in the spec defines zero-length messages, hence we cannot
> support something that is not standard. If your array needs this,
> please submit a TPAR to the NVMe TWG.

We'll still need sanity checking instead of the recount underflow,
I think tearing down the connection here and kicking off error recovery
is probably the best idea.