[PATCH V5 8/9] nvme: core: introduce nvme_force_change_ctrl_state()

[Ming Lei]

When controller is being reset, timeout still may be triggered,
for handling this situation, the contoller state has to be
changed to NVME_CTRL_RESETTING first.

So introduce nvme_force_change_ctrl_state() for this purpose.

Cc: James Smart <james.smart at broadcom.com>
Cc: Jianchao Wang <jianchao.w.wang at oracle.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Sagi Grimberg <sagi at grimberg.me>
Cc: linux-nvme at lists.infradead.org
Cc: Laurence Oberman <loberman at redhat.com>
Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 drivers/nvme/host/core.c | 33 +++++++++++++++++++++++++++++++++
 drivers/nvme/host/nvme.h |  2 ++
 2 files changed, 35 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index adb1743e87f7..af053309c610 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -254,6 +254,39 @@ void nvme_cancel_request(struct request *req, void *data, bool reserved)
 }
 EXPORT_SYMBOL_GPL(nvme_cancel_request);
 
+/* should only be used by EH for handling error during reset */
+void nvme_force_change_ctrl_state(struct nvme_ctrl *ctrl,
+		enum nvme_ctrl_state new_state)
+{
+	enum nvme_ctrl_state old_state;
+	unsigned long flags;
+	bool warn = true;
+
+	spin_lock_irqsave(&ctrl->lock, flags);
+	old_state = ctrl->state;
+	switch (new_state) {
+	case NVME_CTRL_RESETTING:
+		switch (old_state) {
+		case NVME_CTRL_LIVE:
+		case NVME_CTRL_ADMIN_ONLY:
+		case NVME_CTRL_RESETTING:
+		case NVME_CTRL_CONNECTING:
+			warn = false;
+			break;
+		default:
+			break;
+		}
+	default:
+		break;
+	}
+	if (warn)
+		WARN(1, "Make sure you want to change to %d from %d\n",
+				new_state, old_state);
+	ctrl->state = new_state;
+	spin_unlock_irqrestore(&ctrl->lock, flags);
+}
+EXPORT_SYMBOL_GPL(nvme_force_change_ctrl_state);
+
 bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		enum nvme_ctrl_state new_state)
 {
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 021f7147f779..2a68df197c71 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -385,6 +385,8 @@ void nvme_complete_rq(struct request *req);
 void nvme_cancel_request(struct request *req, void *data, bool reserved);
 bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		enum nvme_ctrl_state new_state);
+void nvme_force_change_ctrl_state(struct nvme_ctrl *ctrl,
+		enum nvme_ctrl_state new_state);
 int nvme_disable_ctrl(struct nvme_ctrl *ctrl, u64 cap);
 int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap);
 int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl);
-- 
2.9.5