nvme: split nvme_kill_queues

nvme_kill_queues does two things:

 1) mark the gendisk of all namespaces dead
 2) unquiesce all I/O queues

These used to be be intertwined due to block layer issues, but aren't
any more.  So move the unquiscing of the I/O queues into the callers,
and rename the rest of the function to the now more descriptive
nvme_mark_namespaces_dead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/apple.c

@@ -1153,7 +1153,8 @@ static void apple_nvme_reset_work(struct work_struct *work)
 	nvme_change_ctrl_state(&anv->ctrl, NVME_CTRL_DELETING);
 	nvme_get_ctrl(&anv->ctrl);
 	apple_nvme_disable(anv, false);
-	nvme_kill_queues(&anv->ctrl);
+	nvme_mark_namespaces_dead(&anv->ctrl);
+	nvme_start_queues(&anv->ctrl);
 	if (!queue_work(nvme_wq, &anv->remove_work))
 		nvme_put_ctrl(&anv->ctrl);
 }

drivers/nvme/host/core.c

@@ -4561,8 +4561,10 @@ void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
 	 * removing the namespaces' disks; fail all the queues now to avoid
 	 * potentially having to clean up the failed sync later.
 	 */
-	if (ctrl->state == NVME_CTRL_DEAD)
-		nvme_kill_queues(ctrl);
+	if (ctrl->state == NVME_CTRL_DEAD) {
+		nvme_mark_namespaces_dead(ctrl);
+		nvme_start_queues(ctrl);
+	}
 
 	/* this is a no-op when called from the controller reset handler */
 	nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING_NOIO);
@@ -5108,39 +5110,17 @@ static void nvme_stop_ns_queue(struct nvme_ns *ns)
 		blk_mq_wait_quiesce_done(ns->queue);
 }
 
-/*
- * Prepare a queue for teardown.
- *
- * This must forcibly unquiesce queues to avoid blocking dispatch.
- */
-static void nvme_set_queue_dying(struct nvme_ns *ns)
-{
-	if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
-		return;
-
-	blk_mark_disk_dead(ns->disk);
-	nvme_start_ns_queue(ns);
-}
-
-/**
- * nvme_kill_queues(): Ends all namespace queues
- * @ctrl: the dead controller that needs to end
- *
- * Call this function when the driver determines it is unable to get the
- * controller in a state capable of servicing IO.
- */
-void nvme_kill_queues(struct nvme_ctrl *ctrl)
+/* let I/O to all namespaces fail in preparation for surprise removal */
+void nvme_mark_namespaces_dead(struct nvme_ctrl *ctrl)
 {
 	struct nvme_ns *ns;
 
 	down_read(&ctrl->namespaces_rwsem);
-
 	list_for_each_entry(ns, &ctrl->namespaces, list)
-		nvme_set_queue_dying(ns);
-
+		blk_mark_disk_dead(ns->disk);
 	up_read(&ctrl->namespaces_rwsem);
 }
-EXPORT_SYMBOL_GPL(nvme_kill_queues);
+EXPORT_SYMBOL_GPL(nvme_mark_namespaces_dead);
 
 void nvme_unfreeze(struct nvme_ctrl *ctrl)
 {

drivers/nvme/host/nvme.h

@@ -483,7 +483,6 @@ struct nvme_ns {
 	unsigned long features;
 	unsigned long flags;
 #define NVME_NS_REMOVING	0
-#define NVME_NS_DEAD     	1
 #define NVME_NS_ANA_PENDING	2
 #define NVME_NS_FORCE_RO	3
 #define NVME_NS_READY		4
@@ -758,7 +757,7 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl);
 void nvme_start_queues(struct nvme_ctrl *ctrl);
 void nvme_stop_admin_queue(struct nvme_ctrl *ctrl);
 void nvme_start_admin_queue(struct nvme_ctrl *ctrl);
-void nvme_kill_queues(struct nvme_ctrl *ctrl);
+void nvme_mark_namespaces_dead(struct nvme_ctrl *ctrl);
 void nvme_sync_queues(struct nvme_ctrl *ctrl);
 void nvme_sync_io_queues(struct nvme_ctrl *ctrl);
 void nvme_unfreeze(struct nvme_ctrl *ctrl);

drivers/nvme/host/pci.c

@@ -2788,7 +2788,8 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev)
 	nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
 	nvme_get_ctrl(&dev->ctrl);
 	nvme_dev_disable(dev, false);
-	nvme_kill_queues(&dev->ctrl);
+	nvme_mark_namespaces_dead(&dev->ctrl);
+	nvme_start_queues(&dev->ctrl);
 	if (!queue_work(nvme_wq, &dev->remove_work))
 		nvme_put_ctrl(&dev->ctrl);
 }
@@ -2913,7 +2914,8 @@ static void nvme_reset_work(struct work_struct *work)
 			nvme_unfreeze(&dev->ctrl);
 		} else {
 			dev_warn(dev->ctrl.device, "IO queues lost\n");
-			nvme_kill_queues(&dev->ctrl);
+			nvme_mark_namespaces_dead(&dev->ctrl);
+			nvme_start_queues(&dev->ctrl);
 			nvme_remove_namespaces(&dev->ctrl);
 			nvme_free_tagset(dev);
 		}