Re: [PATCH] nvme: duplicate NQNs check if devices needed

[luanshi <zhangliguang@linux.alibaba.com>]

Hi Christoph,

在 2021/11/30 14:40, Christoph Hellwig 写道:
> On Tue, Nov 30, 2021 at 01:04:55PM +0800, luanshi wrote:
>> Hi Keith,
>>
>> 在 2021/11/30 0:34, Keith Busch 写道:
>>> On Mon, Nov 29, 2021 at 07:18:54PM +0800, Liguang Zhang wrote:
>>>> @@ -2587,6 +2587,9 @@ static struct nvme_subsystem *__nvme_find_get_subsystem(const char *subsysnqn)
>>>>      	lockdep_assert_held(&nvme_subsystems_lock);
>>>>    +	if (strncmp(subsysnqn, "nqn.", 4))
>>>> +		return NULL;
>>> This seems like an arbitrary way to decide not to check for duplicates.
>>> Shouldn't we just add the NVME_QUIRK_IGNORE_DEV_SUBNQN quirk for the
>>> broken controllers?
>> Yeah, add the NVME_QUIRK_IGNORE_DEV_SUBNQN quirk is a way to resolve the
>> problem. I do not
>>
>> have enough controller in my hand, I don't make sure all the controller are
>> covered. And there are some
> What does this broken device report in the subnqn field?
In function nvme_init_subnqn, i add some printk info,

#git diff drivers/nvme/host/core.c
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index e1e574ecf031..d043f4506c37 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2708,6 +2708,7 @@ static void nvme_init_subnqn(struct nvme_subsystem 
*subsys, struct nvme_ctrl *ct

         if(!(ctrl->quirks & NVME_QUIRK_IGNORE_DEV_SUBNQN)) {
                 nqnlen = strnlen(id->subnqn, NVMF_NQN_SIZE);
+             printk("%s: nqnlen=%d, subnqn=%s\n", __func__, nqnlen, 
id->subnqn);
                 if (nqnlen > 0 && nqnlen < NVMF_NQN_SIZE) {
                         strlcpy(subsys->subnqn, id->subnqn, NVMF_NQN_SIZE);
                         return;

I found that:

nqnlen is 1, subnqn filed is filled by space.

nvme_init_subnqn: nqnlen=1 subnqn=


Thanks,

Liguang