[PATCH for-4.5 10/13] NVMe: Move error handling to failed reset handler

[Keith Busch]

This moves the dead queue handling out of the namespace removal path
and into the reset failure path. It fixes a deadlock condition if the
controller fails or link down during del_gendisk.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/nvme/host/core.c | 19 ++-----------------
 drivers/nvme/host/nvme.h |  1 +
 drivers/nvme/host/pci.c  | 22 ++++++++++++++++++++++
 3 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index be27f9f..41b595c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -64,7 +64,7 @@ static void nvme_free_ns(struct kref *kref)
 	kfree(ns);
 }
 
-static void nvme_put_ns(struct nvme_ns *ns)
+void nvme_put_ns(struct nvme_ns *ns)
 {
 	kref_put(&ns->kref, nvme_free_ns);
 }
@@ -1113,28 +1113,13 @@ static struct nvme_ns *nvme_find_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 static void nvme_ns_remove_work(struct work_struct *work)
 {
 	struct nvme_ns *ns = container_of(work, struct nvme_ns, remove_work);
-	bool kill = nvme_io_incapable(ns->ctrl) &&
-			!blk_queue_dying(ns->queue);
-
-	if (kill) {
-		blk_set_queue_dying(ns->queue);
-
-		/*
-		 * The controller was shutdown first if we got here through
-		 * device removal. The shutdown may requeue outstanding
-		 * requests. These need to be aborted immediately so
-		 * del_gendisk doesn't block indefinitely for their completion.
-		 */
-		blk_mq_abort_requeue_list(ns->queue);
-	}
+
 	if (ns->disk->flags & GENHD_FL_UP) {
 		if (blk_get_integrity(ns->disk))
 			blk_integrity_unregister(ns->disk);
 		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
 					&nvme_ns_attr_group);
 		del_gendisk(ns->disk);
-	}
-	if (kill || !blk_queue_dying(ns->queue)) {
 		blk_mq_abort_requeue_list(ns->queue);
 		blk_cleanup_queue(ns->queue);
 	}
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index d330512..19a64b2 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -270,6 +270,7 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
 			dma_addr_t dma_addr, u32 *result);
 int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count);
+void nvme_put_ns(struct nvme_ns *ns);
 
 extern spinlock_t dev_list_lock;
 
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 3381bac..a18e4ab 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1898,11 +1898,33 @@ static void nvme_pci_free_ctrl(struct nvme_ctrl *ctrl)
 	kfree(dev);
 }
 
+static void nvme_kill_ns_queues(struct nvme_dev *dev)
+{
+	struct nvme_ns *ns;
+	struct nvme_ctrl *ctrl = &dev->ctrl;
+
+	nvme_dev_disable(dev, false);
+
+	mutex_lock(&ctrl->namespaces_mutex);
+	list_for_each_entry(ns, &ctrl->namespaces, list) {
+		if (!kref_get_unless_zero(&ns->kref))
+			continue;
+
+		blk_set_queue_dying(ns->queue);
+		blk_mq_abort_requeue_list(ns->queue);
+		blk_mq_start_stopped_hw_queues(ns->queue, true);
+
+		nvme_put_ns(ns);
+	}
+	mutex_unlock(&ctrl->namespaces_mutex);
+}
+
 static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status)
 {
 	dev_warn(dev->dev, "Removing after probe failure status:%d\n", status);
 
 	kref_get(&dev->ctrl.kref);
+	nvme_kill_ns_queues(dev);
 	if (!schedule_work(&dev->remove_work))
 		nvme_put_ctrl(&dev->ctrl);
 }
-- 
2.6.2.307.g37023ba