nvme: nvme-fc: move tagset removal to nvme_fc_delete_ctrl()

Now target is removed from nvme_fc_ctrl_free() which is the ctrl->ref
release handler. And even admin queue is unquiesced there, this way
is definitely wrong because the ctr->ref is grabbed when submitting
command.

And Marco observed that nvme_fc_ctrl_free() can be called from request
completion code path, and trigger kernel warning since request completes
from softirq context.

Fix the issue by moveing target removal into nvme_fc_delete_ctrl(),
which is also aligned with nvme-tcp and nvme-rdma.

Patch originally proposed by Ming Lei, then modified to move the tagset
removal down to after nvme_fc_delete_association() after further testing.

Cc: Marco Patalano <[email protected]>
Cc: Ewan Milne <[email protected]>
Cc: James Smart <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Cc: [email protected]
Tested-by: Marco Patalano <[email protected]>
Reviewed-by: Justin Tee <[email protected]>
Signed-off-by: Ewan D. Milne <[email protected]>
Signed-off-by: Keith Busch <[email protected]>

Author: Ewan D. Milne

drivers/nvme/host/fc.c

@@ -2355,17 +2355,11 @@ nvme_fc_ctrl_free(struct kref *ref)
 		container_of(ref, struct nvme_fc_ctrl, ref);
 	unsigned long flags;
 
-	if (ctrl->ctrl.tagset)
-		nvme_remove_io_tag_set(&ctrl->ctrl);
-
 	/* remove from rport list */
 	spin_lock_irqsave(&ctrl->rport->lock, flags);
 	list_del(&ctrl->ctrl_list);
 	spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 
-	nvme_unquiesce_admin_queue(&ctrl->ctrl);
-	nvme_remove_admin_tag_set(&ctrl->ctrl);
-
 	kfree(ctrl->queues);
 
 	put_device(ctrl->dev);
@@ -3261,11 +3255,18 @@ nvme_fc_delete_ctrl(struct nvme_ctrl *nctrl)
 
 	cancel_work_sync(&ctrl->ioerr_work);
 	cancel_delayed_work_sync(&ctrl->connect_work);
+
 	/*
 	 * kill the association on the link side.  this will block
 	 * waiting for io to terminate
 	 */
 	nvme_fc_delete_association(ctrl);
+
+	if (ctrl->ctrl.tagset)
+		nvme_remove_io_tag_set(&ctrl->ctrl);
+
+	nvme_unquiesce_admin_queue(&ctrl->ctrl);
+	nvme_remove_admin_tag_set(&ctrl->ctrl);
 }
 
 static void