nvme: allow calling nvme_change_ctrl_state from irq context

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>

drivers/nvme/host/core.c

@@ -176,9 +176,10 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		enum nvme_ctrl_state new_state)
 {
 	enum nvme_ctrl_state old_state;
+	unsigned long flags;
 	bool changed = false;
 
-	spin_lock_irq(&ctrl->lock);
+	spin_lock_irqsave(&ctrl->lock, flags);
 
 	old_state = ctrl->state;
 	switch (new_state) {
@@ -239,7 +240,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 	if (changed)
 		ctrl->state = new_state;
 
-	spin_unlock_irq(&ctrl->lock);
+	spin_unlock_irqrestore(&ctrl->lock, flags);
 
 	return changed;
 }