nvmet: enable Discovery Controller AENs

Add functions to find connections requesting Discovery Change events
and send a notification to hosts that maintain an explicit persistent
connection and have and active Asynchronous Event Request pending.
Only Hosts that have access to the Subsystem effected by the change
will receive notifications of Discovery Change event.

Call these functions each time there is a configfs change that effects
the Discover Log Pages.

Set the OAES field in the Identify Controller response to advertise the
support for Asynchronous Event Notifications.
Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com>
Reviewed-by: Phil Cayton <phil.cayton@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/target/configfs.c

@@ -25,6 +25,9 @@
 static const struct config_item_type nvmet_host_type;
 static const struct config_item_type nvmet_subsys_type;
 
+static LIST_HEAD(nvmet_ports_list);
+struct list_head *nvmet_ports = &nvmet_ports_list;
+
 static const struct nvmet_transport_name {
 	u8		type;
 	const char	*name;
@@ -646,7 +649,8 @@ static int nvmet_port_subsys_allow_link(struct config_item *parent,
 	}
 
 	list_add_tail(&link->entry, &port->subsystems);
-	nvmet_genctr++;
+	nvmet_port_disc_changed(port, subsys);
+
 	up_write(&nvmet_config_sem);
 	return 0;
 
@@ -673,7 +677,8 @@ static void nvmet_port_subsys_drop_link(struct config_item *parent,
 
 found:
 	list_del(&p->entry);
-	nvmet_genctr++;
+	nvmet_port_disc_changed(port, subsys);
+
 	if (list_empty(&port->subsystems))
 		nvmet_disable_port(port);
 	up_write(&nvmet_config_sem);
@@ -722,7 +727,8 @@ static int nvmet_allowed_hosts_allow_link(struct config_item *parent,
 			goto out_free_link;
 	}
 	list_add_tail(&link->entry, &subsys->hosts);
-	nvmet_genctr++;
+	nvmet_subsys_disc_changed(subsys, host);
+
 	up_write(&nvmet_config_sem);
 	return 0;
 out_free_link:
@@ -748,7 +754,8 @@ static void nvmet_allowed_hosts_drop_link(struct config_item *parent,
 
 found:
 	list_del(&p->entry);
-	nvmet_genctr++;
+	nvmet_subsys_disc_changed(subsys, host);
+
 	up_write(&nvmet_config_sem);
 	kfree(p);
 }
@@ -787,7 +794,11 @@ static ssize_t nvmet_subsys_attr_allow_any_host_store(struct config_item *item,
 		goto out_unlock;
 	}
 
+	if (subsys->allow_any_host != allow_any_host) {
 		subsys->allow_any_host = allow_any_host;
+		nvmet_subsys_disc_changed(subsys, NULL);
+	}
+
 out_unlock:
 	up_write(&nvmet_config_sem);
 	return ret ? ret : count;
@@ -936,7 +947,7 @@ static ssize_t nvmet_referral_enable_store(struct config_item *item,
 	if (enable)
 		nvmet_referral_enable(parent, port);
 	else
-		nvmet_referral_disable(port);
+		nvmet_referral_disable(parent, port);
 
 	return count;
 inval:
@@ -962,9 +973,10 @@ static struct configfs_attribute *nvmet_referral_attrs[] = {
 
 static void nvmet_referral_release(struct config_item *item)
 {
+	struct nvmet_port *parent = to_nvmet_port(item->ci_parent->ci_parent);
 	struct nvmet_port *port = to_nvmet_port(item);
 
-	nvmet_referral_disable(port);
+	nvmet_referral_disable(parent, port);
 	kfree(port);
 }
 
@@ -1137,6 +1149,8 @@ static void nvmet_port_release(struct config_item *item)
 {
 	struct nvmet_port *port = to_nvmet_port(item);
 
+	list_del(&port->global_entry);
+
 	kfree(port->ana_state);
 	kfree(port);
 }
@@ -1189,6 +1203,8 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
 			port->ana_state[i] = NVME_ANA_INACCESSIBLE;
 	}
 
+	list_add(&port->global_entry, &nvmet_ports_list);
+
 	INIT_LIST_HEAD(&port->entry);
 	INIT_LIST_HEAD(&port->subsystems);
 	INIT_LIST_HEAD(&port->referrals);

drivers/nvme/target/core.c

@@ -130,7 +130,7 @@ static void nvmet_async_event_work(struct work_struct *work)
 	}
 }
 
-static void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
+void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
 		u8 event_info, u8 log_page)
 {
 	struct nvmet_async_event *aen;

drivers/nvme/target/discovery.c

@@ -20,24 +20,82 @@ struct nvmet_subsys *nvmet_disc_subsys;
 
 u64 nvmet_genctr;
 
+static void __nvmet_disc_changed(struct nvmet_port *port,
+				 struct nvmet_ctrl *ctrl)
+{
+	if (ctrl->port != port)
+		return;
+
+	if (nvmet_aen_bit_disabled(ctrl, NVME_AEN_BIT_DISC_CHANGE))
+		return;
+
+	nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE,
+			      NVME_AER_NOTICE_DISC_CHANGED, NVME_LOG_DISC);
+}
+
+void nvmet_port_disc_changed(struct nvmet_port *port,
+			     struct nvmet_subsys *subsys)
+{
+	struct nvmet_ctrl *ctrl;
+
+	nvmet_genctr++;
+
+	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
+		if (subsys && !nvmet_host_allowed(subsys, ctrl->hostnqn))
+			continue;
+
+		__nvmet_disc_changed(port, ctrl);
+	}
+}
+
+static void __nvmet_subsys_disc_changed(struct nvmet_port *port,
+					struct nvmet_subsys *subsys,
+					struct nvmet_host *host)
+{
+	struct nvmet_ctrl *ctrl;
+
+	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
+		if (host && strcmp(nvmet_host_name(host), ctrl->hostnqn))
+			continue;
+
+		__nvmet_disc_changed(port, ctrl);
+	}
+}
+
+void nvmet_subsys_disc_changed(struct nvmet_subsys *subsys,
+			       struct nvmet_host *host)
+{
+	struct nvmet_port *port;
+	struct nvmet_subsys_link *s;
+
+	nvmet_genctr++;
+
+	list_for_each_entry(port, nvmet_ports, global_entry)
+		list_for_each_entry(s, &port->subsystems, entry) {
+			if (s->subsys != subsys)
+				continue;
+			__nvmet_subsys_disc_changed(port, subsys, host);
+		}
+}
+
 void nvmet_referral_enable(struct nvmet_port *parent, struct nvmet_port *port)
 {
 	down_write(&nvmet_config_sem);
 	if (list_empty(&port->entry)) {
 		list_add_tail(&port->entry, &parent->referrals);
 		port->enabled = true;
-		nvmet_genctr++;
+		nvmet_port_disc_changed(parent, NULL);
 	}
 	up_write(&nvmet_config_sem);
 }
 
-void nvmet_referral_disable(struct nvmet_port *port)
+void nvmet_referral_disable(struct nvmet_port *parent, struct nvmet_port *port)
 {
 	down_write(&nvmet_config_sem);
 	if (!list_empty(&port->entry)) {
 		port->enabled = false;
 		list_del_init(&port->entry);
-		nvmet_genctr++;
+		nvmet_port_disc_changed(parent, NULL);
 	}
 	up_write(&nvmet_config_sem);
 }
@@ -136,6 +194,8 @@ static void nvmet_execute_get_disc_log_page(struct nvmet_req *req)
 	hdr->numrec = cpu_to_le64(numrec);
 	hdr->recfmt = cpu_to_le16(0);
 
+	nvmet_clear_aen_bit(req, NVME_AEN_BIT_DISC_CHANGE);
+
 	up_read(&nvmet_config_sem);
 
 	status = nvmet_copy_to_sgl(req, 0, hdr, data_len);
@@ -174,6 +234,8 @@ static void nvmet_execute_identify_disc_ctrl(struct nvmet_req *req)
 	if (req->port->inline_data_size)
 		id->sgls |= cpu_to_le32(1 << 20);
 
+	id->oaes = cpu_to_le32(NVMET_DISC_AEN_CFG_OPTIONAL);
+
 	strlcpy(id->subnqn, ctrl->subsys->subsysnqn, sizeof(id->subnqn));
 
 	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));

drivers/nvme/target/nvmet.h

@@ -139,6 +139,7 @@ struct nvmet_port {
 	struct list_head		subsystems;
 	struct config_group		referrals_group;
 	struct list_head		referrals;
+	struct list_head		global_entry;
 	struct config_group		ana_groups_group;
 	struct nvmet_ana_group		ana_default_group;
 	enum nvme_ana_state		*ana_state;
@@ -422,7 +423,7 @@ int nvmet_enable_port(struct nvmet_port *port);
 void nvmet_disable_port(struct nvmet_port *port);
 
 void nvmet_referral_enable(struct nvmet_port *parent, struct nvmet_port *port);
-void nvmet_referral_disable(struct nvmet_port *port);
+void nvmet_referral_disable(struct nvmet_port *parent, struct nvmet_port *port);
 
 u16 nvmet_copy_to_sgl(struct nvmet_req *req, off_t off, const void *buf,
 		size_t len);
@@ -432,6 +433,14 @@ u16 nvmet_zero_sgl(struct nvmet_req *req, off_t off, size_t len);
 
 u32 nvmet_get_log_page_len(struct nvme_command *cmd);
 
+extern struct list_head *nvmet_ports;
+void nvmet_port_disc_changed(struct nvmet_port *port,
+		struct nvmet_subsys *subsys);
+void nvmet_subsys_disc_changed(struct nvmet_subsys *subsys,
+		struct nvmet_host *host);
+void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
+		u8 event_info, u8 log_page);
+
 #define NVMET_QUEUE_SIZE	1024
 #define NVMET_NR_QUEUES		128
 #define NVMET_MAX_CMD		NVMET_QUEUE_SIZE