release/5.2.40/nvme-pci-move-cqe-check-after-device-shutdown.patch

From 28579e81185fd9adb5d864cf46bf14dd229025ca Mon Sep 17 00:00:00 2001
From: Keith Busch <kbusch@kernel.org>
Date: Thu, 13 Feb 2020 01:41:05 +0900
Subject: [PATCH] nvme/pci: move cqe check after device shutdown

commit fa46c6fb5d61b1f17b06d7c6ef75478b576304c7 upstream.

Many users have reported nvme triggered irq_startup() warnings during
shutdown. The driver uses the nvme queue's irq to synchronize scanning
for completions, and enabling an interrupt affined to only offline CPUs
triggers the alarming warning.

Move the final CQE check to after disabling the device and all
registered interrupts have been torn down so that we do not have any
IRQ to synchronize.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206509
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 94194da1c07b..18c0588c5cd8 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1420,6 +1420,23 @@ static void nvme_disable_admin_queue(struct nvme_dev *dev, bool shutdown)
 	nvme_poll_irqdisable(nvmeq, -1);
 }
 
+/*
+ * Called only on a device that has been disabled and after all other threads
+ * that can check this device's completion queues have synced. This is the
+ * last chance for the driver to see a natural completion before
+ * nvme_cancel_request() terminates all incomplete requests.
+ */
+static void nvme_reap_pending_cqes(struct nvme_dev *dev)
+{
+	u16 start, end;
+	int i;
+
+	for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+		nvme_process_cq(&dev->queues[i], &start, &end, -1);
+		nvme_complete_cqes(&dev->queues[i], start, end);
+	}
+}
+
 static int nvme_cmb_qdepth(struct nvme_dev *dev, int nr_io_queues,
 				int entry_size)
 {
@@ -2239,11 +2256,6 @@ static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode)
 		if (timeout == 0)
 			return false;
 
-		/* handle any remaining CQEs */
-		if (opcode == nvme_admin_delete_cq &&
-		    !test_bit(NVMEQ_DELETE_ERROR, &nvmeq->flags))
-			nvme_poll_irqdisable(nvmeq, -1);
-
 		sent--;
 		if (nr_queues)
 			goto retry;
@@ -2406,6 +2418,7 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
 	nvme_suspend_io_queues(dev);
 	nvme_suspend_queue(&dev->queues[0]);
 	nvme_pci_disable(dev);
+	nvme_reap_pending_cqes(dev);
 
 	blk_mq_tagset_busy_iter(&dev->tagset, nvme_cancel_request, &dev->ctrl);
 	blk_mq_tagset_busy_iter(&dev->admin_tagset, nvme_cancel_request, &dev->ctrl);
-- 
2.7.4