Re: [PATCH] nvme: remove disk after hw queue is started

Ming Lei
2017-05-08T16:15:43Z

On Mon, May 08, 2017 at 11:11:24AM -0400, Keith Busch wrote:
> On Mon, May 08, 2017 at 11:07:20AM -0400, Keith Busch wrote:
> > I'm almost certain the remove_work shouldn't even be running in this
> > case. If the reset work can't transition the controller state correctly,
> > it should assume something is handling the controller.
>
> Here's the more complete version of what I had in mind. Does this solve
> the reported issue?
>
> ---
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 26a5fd0..46a37fb 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1792,7 +1792,7 @@ static void nvme_reset_work(struct work_struct *work)
> nvme_dev_disable(dev, false);
>
> if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING))
> - goto out;
> + return;
>
> result = nvme_pci_enable(dev);
> if (result)
> @@ -1854,7 +1854,7 @@ static void nvme_reset_work(struct work_struct *work)
>
> if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_LIVE)) {
> dev_warn(dev->ctrl.device, "failed to mark controller live\n");
> - goto out;
> + return;
> }
>
> if (dev->online_queues > 1)

This patch looks working, but seems any 'goto out' in this function
may have rick to cause the same race too.

Another solution I thought of is to kill queues earlier, what do you
think about the following patch?

---
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c8541c3dcd19..16740e8c4225 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1892,6 +1892,7 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status)

kref_get(&dev->ctrl.kref);
nvme_dev_disable(dev, false);
+ nvme_kill_queues(&dev->ctrl);
if (!schedule_work(&dev->remove_work))
nvme_put_ctrl(&dev->ctrl);
}
@@ -1998,7 +1999,6 @@ static void nvme_remove_dead_ctrl_work(struct work_struct *work)
struct nvme_dev *dev = container_of(work, struct nvme_dev, remove_work);
struct pci_dev *pdev = to_pci_dev(dev->dev);

- nvme_kill_queues(&dev->ctrl);
if (pci_get_drvdata(pdev))
device_release_driver(&pdev->dev);
nvme_put_ctrl(&dev->ctrl);

Thanks,
Ming