From: Hannes Reinecke <hare@suse.de>
Date: Thu, 16 May 2019 09:39:01 +0200
Subject: [PATCH] nvme: flush scan_work when resetting controller
Patch-Mainline: never, solved differently upstream
References: bsc#1131673

When resetting the controller there is no point whatsoever to
have a scan run in parallel; we cannot access the controller and
we cannot tell which devices are present and which not.
Additionally we'll run a scan after reset anyway.
So flush existing scans, ensuring to short-circuit the scan workqueue
function if the controller state isn't live to avoit lockups.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/nvme/host/core.c | 7 +++++++
 drivers/nvme/host/fc.c   | 1 +
 drivers/nvme/host/rdma.c | 1 +
 3 files changed, 9 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index e536f48ea4dd..1cd8cfe42f60 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1536,6 +1536,9 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 		return -ENODEV;
 	}
 
+	if (ctrl->state != NVME_CTRL_LIVE)
+		return 0;
+
 	id = nvme_identify_ns(ctrl, ns->head->ns_id);
 	if (!id)
 		return -ENODEV;
@@ -3221,6 +3224,8 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
 		return -ENOMEM;
 
 	for (i = 0; i < num_lists; i++) {
+		if (ctrl->state != NVME_CTRL_LIVE)
+			goto free;
 		ret = nvme_identify_ns_list(ctrl, prev, ns_list);
 		if (ret)
 			goto free;
@@ -3299,6 +3304,8 @@ static void nvme_scan_work(struct work_struct *work)
 	if (test_and_clear_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events)) {
 		dev_info(ctrl->device, "rescanning namespaces.\n");
 		nvme_clear_changed_ns_log(ctrl);
+		if (ctrl->state != NVME_CTRL_LIVE)
+			return;
 	}
 
 	if (nvme_identify_ctrl(ctrl, &id))
diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 58d7de4c6c94..a1063c08212d 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -2926,6 +2926,7 @@ nvme_fc_reset_ctrl_work(struct work_struct *work)
 
 	__nvme_fc_terminate_io(ctrl);
 
+	flush_work(&ctrl->ctrl.scan_work);
 	nvme_stop_ctrl(&ctrl->ctrl);
 
 	if (ctrl->rport->remoteport.port_state == FC_OBJSTATE_ONLINE)
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index d42bada25b54..da3b48fbad9e 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1763,6 +1763,7 @@ static void nvme_rdma_reset_ctrl_work(struct work_struct *work)
 
 	nvme_stop_ctrl(&ctrl->ctrl);
 	nvme_rdma_shutdown_ctrl(ctrl, false);
+	flush_work(&ctrl->ctrl.scan_work);
 
 	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING)) {
 		/* state change failure should never happen */
-- 
2.16.4