[PATCH V6 06/11] nvme: pci: freeze queue in nvme_dev_disable() in case of error recovery

Ming Lei
2018-05-16T04:03:08Z

When nvme_dev_disable() is used for error recovery, we should always
freeze queues before shutdown controller:

- reset handler supposes queues are frozen, and will wait_freeze &
unfreeze them explicitly, if queues aren't frozen during nvme_dev_disable(),
reset handler may wait forever even though there isn't any requests
allocated.

- this way may avoid to cancel lots of requests during error recovery

This patch introduces the parameter of 'freeze_queue' for fixing this
issue.

Cc: James Smart <james.smart@broadcom.com>
Cc: Jianchao Wang <jianchao.w.wang@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: linux-nvme@lists.infradead.org
Cc: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/nvme/host/pci.c | 47 ++++++++++++++++++++++++++++++++---------------
1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 6413dad51107..365d1a5ee1eb 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -69,7 +69,8 @@ struct nvme_dev;
struct nvme_queue;

static void nvme_process_cq(struct nvme_queue *nvmeq);
-static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown, bool
+ freeze_queue);

/*
* Represents an NVM Express device. Each nvme_dev is a PCI function.
@@ -1206,7 +1207,7 @@ 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_HANDLED;
}
@@ -1233,7 +1234,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
dev_warn(dev->ctrl.device,
"I/O %d QID %d timeout, disable controller\n",
req->tag, nvmeq->qid);
- nvme_dev_disable(dev, false);
+ nvme_dev_disable(dev, false, false);
nvme_req(req)->flags |= NVME_REQ_CANCELLED;
return BLK_EH_HANDLED;
default:
@@ -1249,7 +1250,7 @@ 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);

/*
@@ -2254,19 +2255,35 @@ static void nvme_pci_disable(struct nvme_dev *dev)
}
}

-static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
+/*
+ * Resetting often follows nvme_dev_disable(), so queues need to be frozen
+ * before resetting.
+ */
+static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown, bool
+ freeze_queue)
{
int i;
bool dead = true;
struct pci_dev *pdev = to_pci_dev(dev->dev);
bool frozen = false;

+ /*
+ * 'freeze_queue' is only valid for non-shutdown, and we do
+ * inline freeze & wait_freeze_timeout for shutdown just for
+ * completing as many as possible requests before shutdown
+ */
+ if (shutdown)
+ freeze_queue = false;
+
+ if (freeze_queue)
+ nvme_start_freeze(&dev->ctrl);
+
mutex_lock(&dev->shutdown_lock);
if (pci_is_enabled(pdev)) {
u32 csts = readl(dev->bar + NVME_REG_CSTS);

- if (dev->ctrl.state == NVME_CTRL_LIVE ||
- dev->ctrl.state == NVME_CTRL_RESETTING) {
+ if (shutdown && (dev->ctrl.state == NVME_CTRL_LIVE ||
+ dev->ctrl.state == NVME_CTRL_RESETTING)) {
nvme_start_freeze(&dev->ctrl);
frozen = true;
}
@@ -2369,7 +2386,7 @@ 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);
if (!queue_work(nvme_wq, &dev->remove_work))
nvme_put_ctrl(&dev->ctrl);
}
@@ -2390,7 +2407,7 @@ 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);

/*
* Introduce CONNECTING state from nvme-fc/rdma transports to mark the
@@ -2639,7 +2656,7 @@ 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, true);
}

static void nvme_reset_done(struct pci_dev *pdev)
@@ -2651,7 +2668,7 @@ 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);
}

/*
@@ -2670,13 +2687,13 @@ 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, false);
+ nvme_dev_disable(dev, false, false);
}

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_free_host_mem(dev);
nvme_dev_remove_admin(dev);
nvme_free_queues(dev, 0);
@@ -2710,7 +2727,7 @@ 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;
}

@@ -2742,7 +2759,7 @@ 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, true);
return PCI_ERS_RESULT_NEED_RESET;
case pci_channel_io_perm_failure:
dev_warn(dev->ctrl.device,
--
2.9.5