[PATCH v2] nvme: Add new clear_ids attribute for passthru targets

[Alan Adamson]

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>
Reviewed-by: Keith Busch <kbusch at kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch at nvidia.com>
---
 drivers/nvme/target/configfs.c | 20 ++++++++++++
 drivers/nvme/target/core.c     |  4 +++
 drivers/nvme/target/nvmet.h    |  1 +
 drivers/nvme/target/passthru.c | 57 ++++++++++++++++++++++++++++++++++
 4 files changed, 82 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..d71ed297ad16 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;
+	struct nvme_ns_id_desc *cur;
+	u16 status = NVME_SC_SUCCESS;
+	int pos, len;
+	bool csi_seen;
+	void *data;
+	u8 csi;
+
+	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;
+}
+
 static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
@@ -152,6 +201,11 @@ static u16 nvmet_passthru_override_id_ns(struct nvmet_req *req)
 	 */
 	id->mc = 0;
 
+	if (req->sq->ctrl->subsys->clear_ids) {
+		memset(id->nguid, 0, NVME_NIDT_NGUID_LEN);
+		memset(id->eui64, 0, NVME_NIDT_EUI64_LEN);
+	}
+
 	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
 
 out_free:
@@ -176,6 +230,9 @@ 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;
-- 
2.31.1