[PATCH v2 3/3] nvme: Add async shutdown support

From: Tanjore Suresh
Date: Tue Apr 12 2022 - 19:23:12 EST

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This works with the asynchronous shutdown mechanism setup for the PCI
drivers and participates to provide both pre and post shutdown
routines at pci_driver structure level.

The shutdown_pre routine starts the shutdown and does not wait for the
shutdown to complete. The shutdown_post routine waits for the shutdown
to complete on individual controllers that this driver instance
controls. This mechanism optimizes to speed up the shutdown in a
system which host many controllers.

Signed-off-by: Tanjore Suresh <tansuresh@xxxxxxxxxx>
---
drivers/nvme/host/core.c | 28 ++++++++++----
drivers/nvme/host/nvme.h | 8 ++++
drivers/nvme/host/pci.c | 80 +++++++++++++++++++++++++---------------
3 files changed, 80 insertions(+), 36 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 677fa4bf76d3..24b08789fd34 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2173,16 +2173,30 @@ EXPORT_SYMBOL_GPL(nvme_enable_ctrl);

int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
{
- unsigned long timeout = jiffies + (ctrl->shutdown_timeout * HZ);
- u32 csts;
int ret;

+ ret = nvme_shutdown_ctrl_start(ctrl);
+ if (ret)
+ return ret;
+ return nvme_wait_for_shutdown_cmpl(ctrl);
+}
+EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl);
+
+int nvme_shutdown_ctrl_start(struct nvme_ctrl *ctrl)
+{
+
ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;

- ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
- if (ret)
- return ret;
+ return ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
+}
+EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl_start);
+
+int nvme_wait_for_shutdown_cmpl(struct nvme_ctrl *ctrl)
+{
+ unsigned long deadline = jiffies + (ctrl->shutdown_timeout * HZ);
+ u32 csts;
+ int ret;

while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
if ((csts & NVME_CSTS_SHST_MASK) == NVME_CSTS_SHST_CMPLT)
@@ -2191,7 +2205,7 @@ int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
msleep(100);
if (fatal_signal_pending(current))
return -EINTR;
- if (time_after(jiffies, timeout)) {
+ if (time_after(jiffies, deadline)) {
dev_err(ctrl->device,
"Device shutdown incomplete; abort shutdown\n");
return -ENODEV;
@@ -2200,7 +2214,7 @@ int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)

return ret;
}
-EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl);
+EXPORT_SYMBOL_GPL(nvme_wait_for_shutdown_cmpl);

static int nvme_configure_timestamp(struct nvme_ctrl *ctrl)
{
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f4b674a8ce20..87f5803ef577 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -170,6 +170,12 @@ enum {
NVME_REQ_USERCMD = (1 << 1),
};

+enum shutdown_type {
+ DO_NOT_SHUTDOWN = 0,
+ SHUTDOWN_TYPE_SYNC = 1,
+ SHUTDOWN_TYPE_ASYNC = 2,
+};
+
static inline struct nvme_request *nvme_req(struct request *req)
{
return blk_mq_rq_to_pdu(req);
@@ -672,6 +678,8 @@ bool nvme_wait_reset(struct nvme_ctrl *ctrl);
int nvme_disable_ctrl(struct nvme_ctrl *ctrl);
int nvme_enable_ctrl(struct nvme_ctrl *ctrl);
int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl);
+int nvme_shutdown_ctrl_start(struct nvme_ctrl *ctrl);
+int nvme_wait_for_shutdown_cmpl(struct nvme_ctrl *ctrl);
int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
const struct nvme_ctrl_ops *ops, unsigned long quirks);
void nvme_uninit_ctrl(struct nvme_ctrl *ctrl);
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 2e98ac3f3ad6..e812509462e8 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -107,7 +107,7 @@ MODULE_PARM_DESC(noacpi, "disable acpi bios quirks");
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, int shutdown_type);
static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode);

/*
@@ -1357,7 +1357,7 @@ 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, DO_NOT_SHUTDOWN);
nvme_reset_ctrl(&dev->ctrl);
return BLK_EH_DONE;
}
@@ -1392,7 +1392,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
"I/O %d QID %d timeout, disable controller\n",
req->tag, nvmeq->qid);
nvme_req(req)->flags |= NVME_REQ_CANCELLED;
- nvme_dev_disable(dev, true);
+ nvme_dev_disable(dev, SHUTDOWN_TYPE_SYNC);
return BLK_EH_DONE;
case NVME_CTRL_RESETTING:
return BLK_EH_RESET_TIMER;
@@ -1410,7 +1410,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
"I/O %d QID %d timeout, reset controller\n",
req->tag, nvmeq->qid);
nvme_req(req)->flags |= NVME_REQ_CANCELLED;
- nvme_dev_disable(dev, false);
+ nvme_dev_disable(dev, DO_NOT_SHUTDOWN);
nvme_reset_ctrl(&dev->ctrl);

return BLK_EH_DONE;
@@ -1503,11 +1503,13 @@ static void nvme_suspend_io_queues(struct nvme_dev *dev)
nvme_suspend_queue(&dev->queues[i]);
}

-static void nvme_disable_admin_queue(struct nvme_dev *dev, bool shutdown)
+static void nvme_disable_admin_queue(struct nvme_dev *dev, int shutdown_type)
{
struct nvme_queue *nvmeq = &dev->queues[0];

- if (shutdown)
+ if (shutdown_type == SHUTDOWN_TYPE_ASYNC)
+ nvme_shutdown_ctrl_start(&dev->ctrl);
+ else if (shutdown_type == SHUTDOWN_TYPE_SYNC)
nvme_shutdown_ctrl(&dev->ctrl);
else
nvme_disable_ctrl(&dev->ctrl);
@@ -2669,7 +2671,7 @@ 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, int shutdown_type)
{
bool dead = true, freeze = false;
struct pci_dev *pdev = to_pci_dev(dev->dev);
@@ -2691,14 +2693,14 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
* Give the controller a chance to complete all entered requests if
* doing a safe shutdown.
*/
- if (!dead && shutdown && freeze)
+ if (!dead && (shutdown_type != DO_NOT_SHUTDOWN) && freeze)
nvme_wait_freeze_timeout(&dev->ctrl, NVME_IO_TIMEOUT);

nvme_stop_queues(&dev->ctrl);

if (!dead && dev->ctrl.queue_count > 0) {
nvme_disable_io_queues(dev);
- nvme_disable_admin_queue(dev, shutdown);
+ nvme_disable_admin_queue(dev, shutdown_type);
}
nvme_suspend_io_queues(dev);
nvme_suspend_queue(&dev->queues[0]);
@@ -2710,12 +2712,12 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
blk_mq_tagset_wait_completed_request(&dev->tagset);
blk_mq_tagset_wait_completed_request(&dev->admin_tagset);

- /*
- * The driver will not be starting up queues again if shutting down so
- * must flush all entered requests to their failed completion to avoid
- * deadlocking blk-mq hot-cpu notifier.
- */
- if (shutdown) {
+ if (shutdown_type == SHUTDOWN_TYPE_SYNC) {
+ /*
+ * The driver will not be starting up queues again if shutting down so
+ * must flush all entered requests to their failed completion to avoid
+ * deadlocking blk-mq hot-cpu notifier.
+ */
nvme_start_queues(&dev->ctrl);
if (dev->ctrl.admin_q && !blk_queue_dying(dev->ctrl.admin_q))
nvme_start_admin_queue(&dev->ctrl);
@@ -2723,11 +2725,11 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
mutex_unlock(&dev->shutdown_lock);
}

-static int nvme_disable_prepare_reset(struct nvme_dev *dev, bool shutdown)
+static int nvme_disable_prepare_reset(struct nvme_dev *dev, int type)
{
if (!nvme_wait_reset(&dev->ctrl))
return -EBUSY;
- nvme_dev_disable(dev, shutdown);
+ nvme_dev_disable(dev, type);
return 0;
}

@@ -2785,7 +2787,7 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev)
*/
nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
nvme_get_ctrl(&dev->ctrl);
- nvme_dev_disable(dev, false);
+ nvme_dev_disable(dev, DO_NOT_SHUTDOWN);
nvme_kill_queues(&dev->ctrl);
if (!queue_work(nvme_wq, &dev->remove_work))
nvme_put_ctrl(&dev->ctrl);
@@ -2810,7 +2812,7 @@ 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, DO_NOT_SHUTDOWN);
nvme_sync_queues(&dev->ctrl);

mutex_lock(&dev->shutdown_lock);
@@ -3151,7 +3153,7 @@ static void nvme_reset_prepare(struct pci_dev *pdev)
* state as pci_dev device lock is held, making it impossible to race
* with ->remove().
*/
- nvme_disable_prepare_reset(dev, false);
+ nvme_disable_prepare_reset(dev, DO_NOT_SHUTDOWN);
nvme_sync_queues(&dev->ctrl);
}

@@ -3163,13 +3165,32 @@ static void nvme_reset_done(struct pci_dev *pdev)
flush_work(&dev->ctrl.reset_work);
}

-static void nvme_shutdown(struct pci_dev *pdev)
+static void nvme_async_shutdown_start(struct pci_dev *pdev)
{
struct nvme_dev *dev = pci_get_drvdata(pdev);

- nvme_disable_prepare_reset(dev, true);
+ nvme_disable_prepare_reset(dev, SHUTDOWN_TYPE_ASYNC);
}

+static void nvme_async_shutdown_end(struct pci_dev *pdev)
+{
+ struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+ mutex_lock(&dev->shutdown_lock);
+ nvme_wait_for_shutdown_cmpl(&dev->ctrl);
+
+ /*
+ * The driver will not be starting up queues again if shutting down so
+ * must flush all entered requests to their failed completion to avoid
+ * deadlocking blk-mq hot-cpu notifier.
+ */
+ nvme_start_queues(&dev->ctrl);
+ if (dev->ctrl.admin_q && !blk_queue_dying(dev->ctrl.admin_q))
+ nvme_start_admin_queue(&dev->ctrl);
+
+ mutex_unlock(&dev->shutdown_lock);
+
+}
static void nvme_remove_attrs(struct nvme_dev *dev)
{
if (dev->attrs_added)
@@ -3191,13 +3212,13 @@ 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, true);
+ nvme_dev_disable(dev, SHUTDOWN_TYPE_SYNC);
}

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, SHUTDOWN_TYPE_SYNC);
nvme_remove_attrs(dev);
nvme_free_host_mem(dev);
nvme_dev_remove_admin(dev);
@@ -3259,7 +3280,7 @@ static int nvme_suspend(struct device *dev)
if (pm_suspend_via_firmware() || !ctrl->npss ||
!pcie_aspm_enabled(pdev) ||
(ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND))
- return nvme_disable_prepare_reset(ndev, true);
+ return nvme_disable_prepare_reset(ndev, SHUTDOWN_TYPE_SYNC);

nvme_start_freeze(ctrl);
nvme_wait_freeze(ctrl);
@@ -3302,7 +3323,7 @@ static int nvme_suspend(struct device *dev)
* Clearing npss forces a controller reset on resume. The
* correct value will be rediscovered then.
*/
- ret = nvme_disable_prepare_reset(ndev, true);
+ ret = nvme_disable_prepare_reset(ndev, SHUTDOWN_TYPE_SYNC);
ctrl->npss = 0;
}
unfreeze:
@@ -3314,7 +3335,7 @@ static int nvme_simple_suspend(struct device *dev)
{
struct nvme_dev *ndev = pci_get_drvdata(to_pci_dev(dev));

- return nvme_disable_prepare_reset(ndev, true);
+ return nvme_disable_prepare_reset(ndev, SHUTDOWN_TYPE_SYNC);
}

static int nvme_simple_resume(struct device *dev)
@@ -3351,7 +3372,7 @@ 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, DO_NOT_SHUTDOWN);
return PCI_ERS_RESULT_NEED_RESET;
case pci_channel_io_perm_failure:
dev_warn(dev->ctrl.device,
@@ -3478,7 +3499,8 @@ static struct pci_driver nvme_driver = {
.id_table = nvme_id_table,
.probe = nvme_probe,
.remove = nvme_remove,
- .shutdown = nvme_shutdown,
+ .async_shutdown_start = nvme_async_shutdown_start,
+ .async_shutdown_end = nvme_async_shutdown_end,
#ifdef CONFIG_PM_SLEEP
.driver = {
.pm = &nvme_dev_pm_ops,
--
2.36.0.rc0.470.gd361397f0d-goog

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Next in thread: Rafael J. Wysocki: "Re: [PATCH v2 1/3] driver core: Support asynchronous driver shutdown"
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