[PATCH v4 6/7] nvme-pci: trigger device coredump on command timeout

[Akinobu Mita]

This enables the nvme driver to trigger a device coredump when command
timeout occurs, and it helps diagnose and debug issues.

This can be tested with fail_io_timeout fault injection.

	# echo 1 > /sys/kernel/debug/fail_io_timeout/probability
	# echo 1 > /sys/kernel/debug/fail_io_timeout/times
	# echo 1 > /sys/block/nvme0n1/io-timeout-fail
	# dd if=/dev/nvme0n1 of=/dev/null

Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Minwoo Im <minwoo.im.dev@xxxxxxxxx>
Cc: Kenneth Heitke <kenneth.heitke@xxxxxxxxx>
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@xxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
* v4
- Abandon the reset if nvme_coredump_logs() returns error code

 drivers/nvme/host/pci.c | 41 +++++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 8a29c52..6436e72 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -87,12 +87,12 @@ MODULE_PARM_DESC(poll_queues, "Number of queues to use for polled IO.");
 struct nvme_dev;
 struct nvme_queue;
 
-static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown, bool dump);
 static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode);
 
-static void __maybe_unused nvme_coredump_init(struct nvme_dev *dev);
-static int __maybe_unused nvme_coredump_logs(struct nvme_dev *dev);
-static void __maybe_unused nvme_coredump_complete(struct nvme_dev *dev);
+static void nvme_coredump_init(struct nvme_dev *dev);
+static int nvme_coredump_logs(struct nvme_dev *dev);
+static void nvme_coredump_complete(struct nvme_dev *dev);
 
 /*
  * Represents an NVM Express device.  Each nvme_dev is a PCI function.
@@ -1280,7 +1280,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
 	 */
 	if (nvme_should_reset(dev, csts)) {
 		nvme_warn_reset(dev, csts);
-		nvme_dev_disable(dev, false);
+		nvme_dev_disable(dev, false, true);
 		nvme_reset_ctrl(&dev->ctrl);
 		return BLK_EH_DONE;
 	}
@@ -1310,7 +1310,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
 		dev_warn_ratelimited(dev->ctrl.device,
 			 "I/O %d QID %d timeout, disable controller\n",
 			 req->tag, nvmeq->qid);
-		nvme_dev_disable(dev, shutdown);
+		nvme_dev_disable(dev, shutdown, true);
 		nvme_req(req)->flags |= NVME_REQ_CANCELLED;
 		return BLK_EH_DONE;
 	default:
@@ -1326,7 +1326,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
 		dev_warn(dev->ctrl.device,
 			 "I/O %d QID %d timeout, reset controller\n",
 			 req->tag, nvmeq->qid);
-		nvme_dev_disable(dev, false);
+		nvme_dev_disable(dev, false, true);
 		nvme_reset_ctrl(&dev->ctrl);
 
 		nvme_req(req)->flags |= NVME_REQ_CANCELLED;
@@ -2382,7 +2382,7 @@ static void nvme_pci_disable(struct nvme_dev *dev)
 	}
 }
 
-static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown, bool dump)
 {
 	bool dead = true;
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
@@ -2407,6 +2407,9 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
 			nvme_wait_freeze_timeout(&dev->ctrl, NVME_IO_TIMEOUT);
 	}
 
+	if (dump)
+		nvme_coredump_init(dev);
+
 	nvme_stop_queues(&dev->ctrl);
 
 	if (!dead && dev->ctrl.queue_count > 0) {
@@ -2477,7 +2480,7 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status)
 	dev_warn(dev->ctrl.device, "Removing after probe failure status: %d\n", status);
 
 	nvme_get_ctrl(&dev->ctrl);
-	nvme_dev_disable(dev, false);
+	nvme_dev_disable(dev, false, false);
 	nvme_kill_queues(&dev->ctrl);
 	if (!queue_work(nvme_wq, &dev->remove_work))
 		nvme_put_ctrl(&dev->ctrl);
@@ -2499,7 +2502,7 @@ static void nvme_reset_work(struct work_struct *work)
 	 * moving on.
 	 */
 	if (dev->ctrl.ctrl_config & NVME_CC_ENABLE)
-		nvme_dev_disable(dev, false);
+		nvme_dev_disable(dev, false, false);
 
 	mutex_lock(&dev->shutdown_lock);
 	result = nvme_pci_enable(dev);
@@ -2536,6 +2539,11 @@ static void nvme_reset_work(struct work_struct *work)
 	if (result)
 		goto out;
 
+	result = nvme_coredump_logs(dev);
+	if (result)
+		goto out;
+	nvme_coredump_complete(dev);
+
 	if (dev->ctrl.oacs & NVME_CTRL_OACS_SEC_SUPP) {
 		if (!dev->ctrl.opal_dev)
 			dev->ctrl.opal_dev =
@@ -2598,6 +2606,7 @@ static void nvme_reset_work(struct work_struct *work)
  out_unlock:
 	mutex_unlock(&dev->shutdown_lock);
  out:
+	nvme_coredump_complete(dev);
 	nvme_remove_dead_ctrl(dev, result);
 }
 
@@ -2788,7 +2797,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 static void nvme_reset_prepare(struct pci_dev *pdev)
 {
 	struct nvme_dev *dev = pci_get_drvdata(pdev);
-	nvme_dev_disable(dev, false);
+	nvme_dev_disable(dev, false, false);
 }
 
 static void nvme_reset_done(struct pci_dev *pdev)
@@ -2800,7 +2809,7 @@ static void nvme_reset_done(struct pci_dev *pdev)
 static void nvme_shutdown(struct pci_dev *pdev)
 {
 	struct nvme_dev *dev = pci_get_drvdata(pdev);
-	nvme_dev_disable(dev, true);
+	nvme_dev_disable(dev, true, false);
 }
 
 /*
@@ -2817,14 +2826,14 @@ static void nvme_remove(struct pci_dev *pdev)
 
 	if (!pci_device_is_present(pdev)) {
 		nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DEAD);
-		nvme_dev_disable(dev, true);
+		nvme_dev_disable(dev, true, false);
 		nvme_dev_remove_admin(dev);
 	}
 
 	flush_work(&dev->ctrl.reset_work);
 	nvme_stop_ctrl(&dev->ctrl);
 	nvme_remove_namespaces(&dev->ctrl);
-	nvme_dev_disable(dev, true);
+	nvme_dev_disable(dev, true, false);
 	nvme_release_cmb(dev);
 	nvme_free_host_mem(dev);
 	nvme_dev_remove_admin(dev);
@@ -2841,7 +2850,7 @@ static int nvme_suspend(struct device *dev)
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct nvme_dev *ndev = pci_get_drvdata(pdev);
 
-	nvme_dev_disable(ndev, true);
+	nvme_dev_disable(ndev, true, false);
 	return 0;
 }
 
@@ -3290,7 +3299,7 @@ static pci_ers_result_t nvme_error_detected(struct pci_dev *pdev,
 	case pci_channel_io_frozen:
 		dev_warn(dev->ctrl.device,
 			"frozen state error detected, reset controller\n");
-		nvme_dev_disable(dev, false);
+		nvme_dev_disable(dev, false, false);
 		return PCI_ERS_RESULT_NEED_RESET;
 	case pci_channel_io_perm_failure:
 		dev_warn(dev->ctrl.device,
-- 
2.7.4