From: Keith Busch <kbusch@kernel.org>
To: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <kbusch@kernel.org>,
Judy Brock <judy.brock@samsung.com>,
Edmund Nadolski <edmund.nadolski@intel.com>,
James Smart <james.smart@broadcom.com>
Subject: [PATCHv4 5/5] nvme: Wait for reset state when required
Date: Fri, 11 Oct 2019 01:57:36 +0900 [thread overview]
Message-ID: <20191010165736.12081-6-kbusch@kernel.org> (raw)
In-Reply-To: <20191010165736.12081-1-kbusch@kernel.org>
Prevent simultaneous controller disabling/enabling tasks from interfering
with each other through a method to wait until the task successfully
transitioned the controller to the RESETTING state. This ensures disabling
the controller will not be interrupted by another reset path, otherwise
a concurrent reset would leave the controller in the wrong state.
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
drivers/nvme/host/core.c | 41 +++++++++++++++++++++++++++++++++--
drivers/nvme/host/nvme.h | 4 ++++
drivers/nvme/host/pci.c | 46 +++++++++++++++++++++++++++-------------
3 files changed, 74 insertions(+), 17 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 0f5a82b7d3a4..7442c99a5ed7 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -126,7 +126,7 @@ static void nvme_queue_scan(struct nvme_ctrl *ctrl)
* code paths that can't be interrupted by other reset attempts. A hot removal
* may prevent this from succeeding.
*/
-static int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
+int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
{
if (ctrl->state != NVME_CTRL_RESETTING)
return -EBUSY;
@@ -134,6 +134,7 @@ static int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
return -EBUSY;
return 0;
}
+EXPORT_SYMBOL_GPL(nvme_try_sched_reset);
int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
{
@@ -384,8 +385,10 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
break;
}
- if (changed)
+ if (changed) {
ctrl->state = new_state;
+ wake_up_all(&ctrl->state_wq);
+ }
spin_unlock_irqrestore(&ctrl->lock, flags);
if (changed && ctrl->state == NVME_CTRL_LIVE)
@@ -394,6 +397,39 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
}
EXPORT_SYMBOL_GPL(nvme_change_ctrl_state);
+/*
+ * Returns true for sink states that can't ever transition back to live.
+ */
+static bool nvme_state_terminal(struct nvme_ctrl *ctrl)
+{
+ switch (ctrl->state) {
+ case NVME_CTRL_NEW:
+ case NVME_CTRL_LIVE:
+ case NVME_CTRL_RESETTING:
+ case NVME_CTRL_CONNECTING:
+ return false;
+ case NVME_CTRL_DELETING:
+ case NVME_CTRL_DEAD:
+ return true;
+ default:
+ WARN_ONCE(1, "Unhandled ctrl state:%d", ctrl->state);
+ return true;
+ }
+}
+
+/*
+ * Waits for the controller state to be resetting, or returns false if it is
+ * not possible to ever transition to that state.
+ */
+bool nvme_wait_reset(struct nvme_ctrl *ctrl)
+{
+ wait_event(ctrl->state_wq,
+ nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING) ||
+ nvme_state_terminal(ctrl));
+ return ctrl->state == NVME_CTRL_RESETTING;
+}
+EXPORT_SYMBOL_GPL(nvme_wait_reset);
+
static void nvme_free_ns_head(struct kref *ref)
{
struct nvme_ns_head *head =
@@ -3999,6 +4035,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
INIT_WORK(&ctrl->async_event_work, nvme_async_event_work);
INIT_WORK(&ctrl->fw_act_work, nvme_fw_act_work);
INIT_WORK(&ctrl->delete_work, nvme_delete_ctrl_work);
+ init_waitqueue_head(&ctrl->state_wq);
INIT_DELAYED_WORK(&ctrl->ka_work, nvme_keep_alive_work);
memset(&ctrl->ka_cmd, 0, sizeof(ctrl->ka_cmd));
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 2ba577271ada..22e8401352c2 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -15,6 +15,7 @@
#include <linux/sed-opal.h>
#include <linux/fault-inject.h>
#include <linux/rcupdate.h>
+#include <linux/wait.h>
#include <trace/events/block.h>
@@ -198,6 +199,7 @@ struct nvme_ctrl {
struct cdev cdev;
struct work_struct reset_work;
struct work_struct delete_work;
+ wait_queue_head_t state_wq;
struct nvme_subsystem *subsys;
struct list_head subsys_entry;
@@ -448,6 +450,7 @@ void nvme_complete_rq(struct request *req);
bool nvme_cancel_request(struct request *req, void *data, bool reserved);
bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
enum nvme_ctrl_state new_state);
+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);
@@ -498,6 +501,7 @@ int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count);
void nvme_stop_keep_alive(struct nvme_ctrl *ctrl);
int nvme_reset_ctrl(struct nvme_ctrl *ctrl);
int nvme_reset_ctrl_sync(struct nvme_ctrl *ctrl);
+int nvme_try_sched_reset(struct nvme_ctrl *ctrl);
int nvme_delete_ctrl(struct nvme_ctrl *ctrl);
int nvme_get_log(struct nvme_ctrl *ctrl, u32 nsid, u8 log_page, u8 lsp,
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 7d0de87d733d..4fcfd01f350d 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2463,6 +2463,14 @@ 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)
+{
+ if (!nvme_wait_reset(&dev->ctrl))
+ return -EBUSY;
+ nvme_dev_disable(dev, shutdown);
+ return 0;
+}
+
static int nvme_setup_prp_pools(struct nvme_dev *dev)
{
dev->prp_page_pool = dma_pool_create("prp list page", dev->dev,
@@ -2510,6 +2518,11 @@ static void nvme_pci_free_ctrl(struct nvme_ctrl *ctrl)
static void nvme_remove_dead_ctrl(struct nvme_dev *dev)
{
+ /*
+ * Set state to deleting now to avoid blocking nvme_wait_reset(), which
+ * may be holding this pci_dev's device lock.
+ */
+ nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
nvme_get_ctrl(&dev->ctrl);
nvme_dev_disable(dev, false);
nvme_kill_queues(&dev->ctrl);
@@ -2835,19 +2848,28 @@ 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);
+
+ /*
+ * We don't need to check the return value from waiting for the reset
+ * state as pci_dev device lock is held, making it impossible to race
+ * with ->remove().
+ */
+ nvme_disable_prepare_reset(dev, false);
+ nvme_sync_queues(&dev->ctrl);
}
static void nvme_reset_done(struct pci_dev *pdev)
{
struct nvme_dev *dev = pci_get_drvdata(pdev);
- nvme_reset_ctrl_sync(&dev->ctrl);
+
+ if (!nvme_try_sched_reset(&dev->ctrl))
+ flush_work(&dev->ctrl.reset_work);
}
static void nvme_shutdown(struct pci_dev *pdev)
{
struct nvme_dev *dev = pci_get_drvdata(pdev);
- nvme_dev_disable(dev, true);
+ nvme_disable_prepare_reset(dev, true);
}
/*
@@ -2900,7 +2922,7 @@ static int nvme_resume(struct device *dev)
if (ndev->last_ps == U32_MAX ||
nvme_set_power_state(ctrl, ndev->last_ps) != 0)
- nvme_reset_ctrl(ctrl);
+ return nvme_try_sched_reset(&ndev->ctrl);
return 0;
}
@@ -2928,10 +2950,8 @@ 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)) {
- nvme_dev_disable(ndev, true);
- return 0;
- }
+ (ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND))
+ return nvme_disable_prepare_reset(ndev, true);
nvme_start_freeze(ctrl);
nvme_wait_freeze(ctrl);
@@ -2963,9 +2983,8 @@ static int nvme_suspend(struct device *dev)
* Clearing npss forces a controller reset on resume. The
* correct value will be resdicovered then.
*/
- nvme_dev_disable(ndev, true);
+ ret = nvme_disable_prepare_reset(ndev, true);
ctrl->npss = 0;
- ret = 0;
}
unfreeze:
nvme_unfreeze(ctrl);
@@ -2975,9 +2994,7 @@ static int nvme_suspend(struct device *dev)
static int nvme_simple_suspend(struct device *dev)
{
struct nvme_dev *ndev = pci_get_drvdata(to_pci_dev(dev));
-
- nvme_dev_disable(ndev, true);
- return 0;
+ return nvme_disable_prepare_reset(ndev, true);
}
static int nvme_simple_resume(struct device *dev)
@@ -2985,8 +3002,7 @@ static int nvme_simple_resume(struct device *dev)
struct pci_dev *pdev = to_pci_dev(dev);
struct nvme_dev *ndev = pci_get_drvdata(pdev);
- nvme_reset_ctrl(&ndev->ctrl);
- return 0;
+ return nvme_try_sched_reset(&ndev->ctrl);
}
static const struct dev_pm_ops nvme_dev_pm_ops = {
--
2.21.0
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next prev parent reply other threads:[~2019-10-10 16:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 16:57 [PATCHv4 0/5] nvme: double reset prevention Keith Busch
2019-10-10 16:57 ` [PATCHv4 1/5] nvme-pci: Free tagset if no IO queues Keith Busch
2019-10-10 16:57 ` [PATCHv4 2/5] nvme: Remove ADMIN_ONLY state Keith Busch
2019-10-10 16:57 ` [PATCHv4 3/5] nvme: Restart request timers in resetting state Keith Busch
2019-10-10 16:57 ` [PATCHv4 4/5] nvme: Prevent resets during paused controller state Keith Busch
2019-10-10 16:57 ` Keith Busch [this message]
2019-10-16 0:56 ` [PATCHv4 5/5] nvme: Wait for reset state when required Balbir Singh
2019-10-10 17:09 ` [PATCHv4 0/5] nvme: double reset prevention Nadolski, Edmund
2019-10-11 15:58 ` Nadolski, Edmund
2019-10-11 16:27 ` Keith Busch
2019-10-14 7:15 ` Christoph Hellwig
2019-10-14 15:06 ` Keith Busch
2019-10-14 7:14 ` Christoph Hellwig
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