nvmet: add AEN configuration support

AEN configuration via the 'Get Features' and 'Set Features' admin
command is mandatory, so we should be implemeting handling for it.
Signed-off-by: Hannes Reinecke <hare@suse.com>
[hch: use WRITE_ONCE, check for invalid values]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

drivers/nvme/target/admin-cmd.c

@@ -189,7 +189,7 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
 
 	/* XXX: figure out what to do about RTD3R/RTD3 */
-	id->oaes = cpu_to_le32(1 << 8);
+	id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
 	id->ctratt = cpu_to_le32(1 << 0);
 
 	id->oacs = 0;
@@ -435,6 +435,16 @@ static void nvmet_execute_set_features(struct nvmet_req *req)
 		req->sq->ctrl->kato = DIV_ROUND_UP(val32, 1000);
 		nvmet_set_result(req, req->sq->ctrl->kato);
 		break;
+	case NVME_FEAT_ASYNC_EVENT:
+		val32 = le32_to_cpu(req->cmd->common.cdw10[1]);
+		if (val32 & ~NVMET_AEN_CFG_ALL) {
+			status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+			break;
+		}
+
+		WRITE_ONCE(req->sq->ctrl->aen_enabled, val32);
+		nvmet_set_result(req, val32);
+		break;
 	case NVME_FEAT_HOST_ID:
 		status = NVME_SC_CMD_SEQ_ERROR | NVME_SC_DNR;
 		break;
@@ -473,9 +483,10 @@ static void nvmet_execute_get_features(struct nvmet_req *req)
 		break;
 	case NVME_FEAT_WRITE_ATOMIC:
 		break;
+#endif
 	case NVME_FEAT_ASYNC_EVENT:
+		nvmet_set_result(req, READ_ONCE(req->sq->ctrl->aen_enabled));
 		break;
-#endif
 	case NVME_FEAT_VOLATILE_WC:
 		nvmet_set_result(req, 1);
 		break;

drivers/nvme/target/core.c

@@ -174,6 +174,8 @@ static void nvmet_ns_changed(struct nvmet_subsys *subsys, u32 nsid)
 
 	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
 		nvmet_add_to_changed_ns_log(ctrl, cpu_to_le32(nsid));
+		if (!(READ_ONCE(ctrl->aen_enabled) & NVME_AEN_CFG_NS_ATTR))
+			continue;
 		nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE,
 				NVME_AER_NOTICE_NS_CHANGED,
 				NVME_LOG_CHANGED_NS);
@@ -861,6 +863,7 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 
 	kref_init(&ctrl->ref);
 	ctrl->subsys = subsys;
+	WRITE_ONCE(ctrl->aen_enabled, NVMET_AEN_CFG_OPTIONAL);
 
 	ctrl->changed_ns_list = kmalloc_array(NVME_MAX_CHANGED_NAMESPACES,
 			sizeof(__le32), GFP_KERNEL);

drivers/nvme/target/nvmet.h

@@ -30,6 +30,21 @@
 #define NVMET_ASYNC_EVENTS		4
 #define NVMET_ERROR_LOG_SLOTS		128
 
+
+/*
+ * Supported optional AENs:
+ */
+#define NVMET_AEN_CFG_OPTIONAL \
+	NVME_AEN_CFG_NS_ATTR
+
+/*
+ * Plus mandatory SMART AENs (we'll never send them, but allow enabling them):
+ */
+#define NVMET_AEN_CFG_ALL \
+	(NVME_SMART_CRIT_SPARE | NVME_SMART_CRIT_TEMPERATURE | \
+	 NVME_SMART_CRIT_RELIABILITY | NVME_SMART_CRIT_MEDIA | \
+	 NVME_SMART_CRIT_VOLATILE_MEMORY | NVMET_AEN_CFG_OPTIONAL)
+
 /* Helper Macros when NVMe error is NVME_SC_CONNECT_INVALID_PARAM
  * The 16 bit shift is to set IATTR bit to 1, which means offending
  * offset starts in the data section of connect()
@@ -123,6 +138,7 @@ struct nvmet_ctrl {
 	u16			cntlid;
 	u32			kato;
 
+	u32			aen_enabled;
 	struct nvmet_req	*async_event_cmds[NVMET_ASYNC_EVENTS];
 	unsigned int		nr_async_event_cmds;
 	struct list_head	async_events;