[bug report]unhandled identify cns 6 on qid 0

[Yi Zhang]

Hi Keith
I found this error log during blktests[2] on linux-block/for-next, it
was introduced with [1] and seems no handler for NVME_ID_CNS_CS_CTRL,
could you help check it?

[1]
commit 5befc7c26e5a98cd49789fb1beb52c62bd472dba
Author: Keith Busch <kbusch at kernel.org>
Date:   Wed Mar 24 16:18:05 2021 -0700

    nvme: implement non-mdts command limits


+       c.identify.cns = NVME_ID_CNS_CS_CTRL;

static void nvmet_execute_identify(struct nvmet_req *req)
{
        if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
                return;

        switch (req->cmd->identify.cns) {
        case NVME_ID_CNS_NS:
                return nvmet_execute_identify_ns(req);
        case NVME_ID_CNS_CTRL:
                return nvmet_execute_identify_ctrl(req);
        case NVME_ID_CNS_NS_ACTIVE_LIST:
                return nvmet_execute_identify_nslist(req);
        case NVME_ID_CNS_NS_DESC_LIST:
                return nvmet_execute_identify_desclist(req);
        }

        pr_err("unhandled identify cns %d on qid %d\n",
               req->cmd->identify.cns, req->sq->qid);

[2]
#./check nvme/010
[  493.632730] run blktests nvme/010 at 2021-04-28 04:19:28
[  493.669330] loop0: detected capacity change from 0 to 2097152
[  493.685798] nvmet: adding nsid 1 to subsystem blktests-subsystem-1
[  493.689397] nvmet: creating controller 1 for subsystem
blktests-subsystem-1 for NQN
nqn.2014-08.org.nvmexpress:uuid:48741e3a-3c7e-428b-877f-b78897ab0f61.
[  493.689439] nvmet: unhandled identify cns 6 on qid 0
[  493.694412] nvme nvme0: creating 32 I/O queues.
[  493.695351] nvme nvme0: new ctrl: "blktests-subsystem-1"
[  497.870910] nvme nvme0: Removing ctrl: NQN "blktests-subsystem-1"

Thanks
Yi