NVMe: Controller resets

index 52cf479..f401e2b 100644
@@ -58,6 +58,7 @@ module_param(use_threaded_interrupts, int, 0);
 static DEFINE_SPINLOCK(dev_list_lock);
 static LIST_HEAD(dev_list);
 static struct task_struct *nvme_thread;
+static struct workqueue_struct *nvme_workq;
 
 /*
  * An NVM Express queue.  Each device has at least two (one for admin

@@ -1605,6 +1606,12 @@ static int nvme_kthread(void *data)
 		spin_lock(&dev_list_lock);
 		list_for_each_entry(dev, &dev_list, node) {
 			int i;
+			if (readl(&dev->bar->csts) & NVME_CSTS_CFS) {
+				dev_warn(&dev->pci_dev->dev,
+					"failed status, reset controller\n");
+				queue_work(nvme_workq, &dev->ws);
+				continue;
+			}
 			for (i = 0; i < dev->queue_count; i++) {
 				struct nvme_queue *nvmeq = dev->queues[i];
 				if (!nvmeq)

@@ -2151,6 +2158,19 @@ static int nvme_dev_start(struct nvme_dev *dev)
 	return result;
 }
 
+static void nvme_dev_reset(struct nvme_dev *dev)
+{
+	nvme_dev_shutdown(dev);
+	if (nvme_dev_start(dev))
+		nvme_free_queues(dev);
+}
+
+static void nvme_reset_failed_dev(struct work_struct *ws)
+{
+	struct nvme_dev *dev = container_of(ws, struct nvme_dev, ws);
+	nvme_dev_reset(dev);
+}
+
 static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	int result = -ENOMEM;

@@ -2178,6 +2198,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (result)
 		goto release;
 
+	INIT_WORK(&dev->ws, nvme_reset_failed_dev);
 	result = nvme_dev_start(dev);
 	if (result)
 		goto release_pools;

@@ -2288,9 +2309,14 @@ static int __init nvme_init(void)
 	if (IS_ERR(nvme_thread))
 		return PTR_ERR(nvme_thread);
 
+	result = -ENOMEM;
+	nvme_workq = create_workqueue("nvme");
+	if (!nvme_workq)
+		goto kill_kthread;
+
 	result = register_blkdev(nvme_major, "nvme");
 	if (result < 0)
-		goto kill_thread;
+		goto kill_workq;
 	else if (result > 0)
 		nvme_major = result;
 

@@ -2301,6 +2327,8 @@ static int __init nvme_init(void)
 
  unregister_blkdev:
 	unregister_blkdev(nvme_major, "nvme");
+ kill_workq:
+	destroy_workqueue(nvme_workq);
  kill_kthread:
 	kthread_stop(nvme_thread);
 	return result;

index 26ebcf4..612e640 100644
@@ -87,6 +87,7 @@ struct nvme_dev {
 	struct list_head namespaces;
 	struct kref kref;
 	struct miscdevice miscdev;
+	struct work_struct ws;
 	char name[12];
 	char serial[20];
 	char model[40];

index f401e2b..ee29e2e 100644
@@ -2171,6 +2171,17 @@ static void nvme_reset_failed_dev(struct work_struct *ws)
 	nvme_dev_reset(dev);
 }
 
+static ssize_t nvme_reset(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct pci_dev  *pdev = container_of(dev, struct pci_dev, dev);
+	struct nvme_dev *ndev = pci_get_drvdata(pdev);
+
+	nvme_dev_reset(ndev);	
+	return count;
+}
+static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_reset);
+
 static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	int result = -ENOMEM;

@@ -2217,6 +2228,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto remove;
 
 	kref_init(&dev->kref);
+	device_create_file(&pdev->dev, &dev_attr_reset_controller);
 	return 0;
 
  remove:

@@ -2238,6 +2250,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 static void nvme_remove(struct pci_dev *pdev)
 {
 	struct nvme_dev *dev = pci_get_drvdata(pdev);
+	device_remove_file(&pdev->dev, &dev_attr_reset_controller);
 	misc_deregister(&dev->miscdev);
 	kref_put(&dev->kref, nvme_free_dev);
 }