3 files changed, 44 insertions, 12 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2a69d735efbc..609307ca9e4d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -232,6 +232,15 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 
 	old_state = ctrl->state;
 	switch (new_state) {
+	case NVME_CTRL_ADMIN_ONLY:
+		switch (old_state) {
+		case NVME_CTRL_RESETTING:
+			changed = true;
+			/* FALLTHRU */
+		default:
+			break;
+		}
+		break;
 	case NVME_CTRL_LIVE:
 		switch (old_state) {
 		case NVME_CTRL_NEW:
@@ -247,6 +256,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		switch (old_state) {
 		case NVME_CTRL_NEW:
 		case NVME_CTRL_LIVE:
+		case NVME_CTRL_ADMIN_ONLY:
 			changed = true;
 			/* FALLTHRU */
 		default:
@@ -266,6 +276,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 	case NVME_CTRL_DELETING:
 		switch (old_state) {
 		case NVME_CTRL_LIVE:
+		case NVME_CTRL_ADMIN_ONLY:
 		case NVME_CTRL_RESETTING:
 		case NVME_CTRL_RECONNECTING:
 			changed = true;
@@ -2336,8 +2347,14 @@ static int nvme_dev_open(struct inode *inode, struct file *file)
 	struct nvme_ctrl *ctrl =
 		container_of(inode->i_cdev, struct nvme_ctrl, cdev);
 
-	if (ctrl->state != NVME_CTRL_LIVE)
+	switch (ctrl->state) {
+	case NVME_CTRL_LIVE:
+	case NVME_CTRL_ADMIN_ONLY:
+		break;
+	default:
 		return -EWOULDBLOCK;
+	}
+
 	file->private_data = ctrl;
 	return 0;
 }
@@ -2601,6 +2618,7 @@ static ssize_t nvme_sysfs_show_state(struct device *dev,
 	static const char *const state_name[] = {
 		[NVME_CTRL_NEW]		= "new",
 		[NVME_CTRL_LIVE]	= "live",
+		[NVME_CTRL_ADMIN_ONLY]	= "only-admin",
 		[NVME_CTRL_RESETTING]	= "resetting",
 		[NVME_CTRL_RECONNECTING]= "reconnecting",
 		[NVME_CTRL_DELETING]	= "deleting",
@@ -3073,6 +3091,8 @@ static void nvme_scan_work(struct work_struct *work)
 	if (ctrl->state != NVME_CTRL_LIVE)
 		return;
 
+	WARN_ON_ONCE(!ctrl->tagset);
+
 	if (nvme_identify_ctrl(ctrl, &id))
 		return;
 
@@ -3093,8 +3113,7 @@ static void nvme_scan_work(struct work_struct *work)
 void nvme_queue_scan(struct nvme_ctrl *ctrl)
 {
 	/*
-	 * Do not queue new scan work when a controller is reset during
-	 * removal.
+	 * Only new queue scan work when admin and IO queues are both alive
 	 */
 	if (ctrl->state == NVME_CTRL_LIVE)
 		queue_work(nvme_wq, &ctrl->scan_work);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ea1aa5283e8e..eecf71ce6e75 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -119,6 +119,7 @@ static inline struct nvme_request *nvme_req(struct request *req)
 enum nvme_ctrl_state {
 	NVME_CTRL_NEW,
 	NVME_CTRL_LIVE,
+	NVME_CTRL_ADMIN_ONLY,    /* Only admin queue live */
 	NVME_CTRL_RESETTING,
 	NVME_CTRL_RECONNECTING,
 	NVME_CTRL_DELETING,
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index add7b18d825d..62119078c2bf 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2035,13 +2035,12 @@ static void nvme_disable_io_queues(struct nvme_dev *dev, int queues)
 }
 
 /*
- * Return: error value if an error occurred setting up the queues or calling
- * Identify Device.  0 if these succeeded, even if adding some of the
- * namespaces failed.  At the moment, these failures are silent.  TBD which
- * failures should be reported.
+ * return error value only when tagset allocation failed
  */
 static int nvme_dev_add(struct nvme_dev *dev)
 {
+	int ret;
+
 	if (!dev->ctrl.tagset) {
 		dev->tagset.ops = &nvme_mq_ops;
 		dev->tagset.nr_hw_queues = dev->online_queues - 1;
@@ -2057,8 +2056,12 @@ static int nvme_dev_add(struct nvme_dev *dev)
 		dev->tagset.flags = BLK_MQ_F_SHOULD_MERGE;
 		dev->tagset.driver_data = dev;
 
-		if (blk_mq_alloc_tag_set(&dev->tagset))
-			return 0;
+		ret = blk_mq_alloc_tag_set(&dev->tagset);
+		if (ret) {
+			dev_warn(dev->ctrl.device,
+				"IO queues tagset allocation failed %d\n", ret);
+			return ret;
+		}
 		dev->ctrl.tagset = &dev->tagset;
 
 		nvme_dbbuf_set(dev);
@@ -2291,6 +2294,7 @@ static void nvme_reset_work(struct work_struct *work)
 		container_of(work, struct nvme_dev, ctrl.reset_work);
 	bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
 	int result = -ENODEV;
+	enum nvme_ctrl_state new_state = NVME_CTRL_LIVE;
 
 	if (WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING))
 		goto out;
@@ -2354,15 +2358,23 @@ static void nvme_reset_work(struct work_struct *work)
 		dev_warn(dev->ctrl.device, "IO queues not created\n");
 		nvme_kill_queues(&dev->ctrl);
 		nvme_remove_namespaces(&dev->ctrl);
+		new_state = NVME_CTRL_ADMIN_ONLY;
 	} else {
 		nvme_start_queues(&dev->ctrl);
 		nvme_wait_freeze(&dev->ctrl);
-		nvme_dev_add(dev);
+		/* hit this only when allocate tagset fails */
+		if (nvme_dev_add(dev))
+			new_state = NVME_CTRL_ADMIN_ONLY;
 		nvme_unfreeze(&dev->ctrl);
 	}
 
-	if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_LIVE)) {
-		dev_warn(dev->ctrl.device, "failed to mark controller live\n");
+	/*
+	 * If only admin queue live, keep it to do further investigation or
+	 * recovery.
+	 */
+	if (!nvme_change_ctrl_state(&dev->ctrl, new_state)) {
+		dev_warn(dev->ctrl.device,
+			"failed to mark controller state %d\n", new_state);
 		goto out;
 	}