[PATCH] Add new clear_ids attribute for passthru targets

[Sagi Grimberg]

On 6/23/22 01:47, Alan Adamson wrote:
> If the clear_ids attribute is set to true, the EUI/GUID/UUID is
> cleared for the passthru target.  By default, loop targets will
> set clear_ids to true.
> 
> This resolves an issue where a connect to a passthru target fails
> when using a trtype of 'loop' because EUI/GUID/UUID is not unique.
> 
> Signed-off-by: Alan Adamson <alan.adamson at oracle.com>
> ---
>   drivers/nvme/target/configfs.c | 20 ++++++++++++
>   drivers/nvme/target/core.c     |  4 +++
>   drivers/nvme/target/nvmet.h    |  1 +
>   drivers/nvme/target/passthru.c | 58 ++++++++++++++++++++++++++++++++++
>   4 files changed, 83 insertions(+)
> 
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index e44b2988759e..ff77c3d2354f 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -773,11 +773,31 @@ static ssize_t nvmet_passthru_io_timeout_store(struct config_item *item,
>   }
>   CONFIGFS_ATTR(nvmet_passthru_, io_timeout);
>   
> +static ssize_t nvmet_passthru_clear_ids_show(struct config_item *item,
> +		char *page)
> +{
> +	return sprintf(page, "%u\n", to_subsys(item->ci_parent)->clear_ids);
> +}
> +
> +static ssize_t nvmet_passthru_clear_ids_store(struct config_item *item,
> +		const char *page, size_t count)
> +{
> +	struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
> +	unsigned int clear_ids;
> +
> +	if (kstrtouint(page, 0, &clear_ids))
> +		return -EINVAL;
> +	subsys->clear_ids = clear_ids;
> +	return count;
> +}
> +CONFIGFS_ATTR(nvmet_passthru_, clear_ids);
> +
>   static struct configfs_attribute *nvmet_passthru_attrs[] = {
>   	&nvmet_passthru_attr_device_path,
>   	&nvmet_passthru_attr_enable,
>   	&nvmet_passthru_attr_admin_timeout,
>   	&nvmet_passthru_attr_io_timeout,
> +	&nvmet_passthru_attr_clear_ids,
>   	NULL,
>   };
>   
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index 90e75324dae0..d4203d582343 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -1374,6 +1374,10 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
>   	ctrl->port = req->port;
>   	ctrl->ops = req->ops;
>   
> +	/* By default, set loop targets to clear IDS by default */
> +	if (ctrl->port->disc_addr.trtype == NVMF_TRTYPE_LOOP)
> +		subsys->clear_ids = 1;
> +
>   	INIT_WORK(&ctrl->async_event_work, nvmet_async_event_work);
>   	INIT_LIST_HEAD(&ctrl->async_events);
>   	INIT_RADIX_TREE(&ctrl->p2p_ns_map, GFP_KERNEL);
> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
> index 69818752a33a..2b3e5719f24e 100644
> --- a/drivers/nvme/target/nvmet.h
> +++ b/drivers/nvme/target/nvmet.h
> @@ -249,6 +249,7 @@ struct nvmet_subsys {
>   	struct config_group	passthru_group;
>   	unsigned int		admin_timeout;
>   	unsigned int		io_timeout;
> +	unsigned int		clear_ids;
>   #endif /* CONFIG_NVME_TARGET_PASSTHRU */
>   
>   #ifdef CONFIG_BLK_DEV_ZONED
> diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
> index b1f7efab3918..e8c033fbdb5c 100644
> --- a/drivers/nvme/target/passthru.c
> +++ b/drivers/nvme/target/passthru.c
> @@ -30,6 +30,55 @@ void nvmet_passthrough_override_cap(struct nvmet_ctrl *ctrl)
>   		ctrl->cap &= ~(1ULL << 43);
>   }
>   
> +static u16 nvmet_passthru_override_id_descs(struct nvmet_req *req)
> +{
> +	struct nvmet_ctrl *ctrl = req->sq->ctrl;
> +	void *data;
> +	struct nvme_ns_id_desc *cur;
> +	u16 status = NVME_SC_SUCCESS;
> +	u8 csi;
> +	int pos, len;
> +	bool csi_seen;
> +
> +	if (!ctrl->subsys->clear_ids)
> +		return status;
> +
> +	data = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
> +	if (!data)
> +		return NVME_SC_INTERNAL;
> +
> +	status = nvmet_copy_from_sgl(req, 0, data, NVME_IDENTIFY_DATA_SIZE);
> +	if (status)
> +		goto out_free;
> +
> +	for (pos = 0; pos < NVME_IDENTIFY_DATA_SIZE; pos += len) {
> +		cur = data + pos;
> +
> +		if (cur->nidl == 0)
> +			break;
> +		len = cur->nidl;
> +		if (cur->nidt == NVME_NIDT_CSI) {
> +			memcpy(&csi, data + pos + sizeof(struct nvme_ns_id_desc),
> +			       NVME_NIDT_CSI_LEN);
> +			csi_seen = 1;
> +			break;
> +		}
> +		len += sizeof(struct nvme_ns_id_desc);
> +	}
> +
> +	memset(data, 0, NVME_IDENTIFY_DATA_SIZE);
> +	if (csi_seen) {
> +		cur = data;
> +		cur->nidt = NVME_NIDT_CSI;
> +		cur->nidl = NVME_NIDT_CSI_LEN;
> +		memcpy(data + sizeof(struct nvme_ns_id_desc), &csi,  NVME_NIDT_CSI_LEN);
> +	}
> +	status = nvmet_copy_to_sgl(req, 0, data, NVME_IDENTIFY_DATA_SIZE);
> +out_free:
> +	kfree(data);
> +	return status;
> +}

I can't understand what this function does...

> +
>   static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
>   {
>   	struct nvmet_ctrl *ctrl = req->sq->ctrl;
> @@ -127,6 +176,7 @@ static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
>   
>   static u16 nvmet_passthru_override_id_ns(struct nvmet_req *req)
>   {
> +	struct nvmet_ctrl *ctrl = req->sq->ctrl;
>   	u16 status = NVME_SC_SUCCESS;
>   	struct nvme_id_ns *id;
>   	int i;
> @@ -152,6 +202,11 @@ static u16 nvmet_passthru_override_id_ns(struct nvmet_req *req)
>   	 */
>   	id->mc = 0;
>   
> +	if (ctrl->subsys->clear_ids) {
> +		memset(id->nguid, 0, NVME_NIDT_NGUID_LEN);
> +		memset(id->eui64, 0, NVME_NIDT_EUI64_LEN);

What about uuid?

> +	}
> +
>   	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
>   
>   out_free:
> @@ -176,6 +231,9 @@ static void nvmet_passthru_execute_cmd_work(struct work_struct *w)
>   		case NVME_ID_CNS_NS:
>   			nvmet_passthru_override_id_ns(req);
>   			break;
> +		case NVME_ID_CNS_NS_DESC_LIST:
> +			nvmet_passthru_override_id_descs(req);
> +			break;
>   		}
>   	} else if (status < 0)
>   		status = NVME_SC_INTERNAL;