From c1ac9a4b0797ca8bb4470f863a5f78ef1ab13bed Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Wed, 4 Sep 2019 10:06:11 -0600 Subject: nvme: Wait for reset state when required Prevent simultaneous controller disabling/enabling tasks from interfering with each other through a function 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 may leave the controller in the wrong state. Tested-by: Edmund Nadolski Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch --- 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 e94fa693dd4b..fa7ba09dca77 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 = @@ -3998,6 +4034,7 @@ 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 #include #include +#include #include @@ -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 e7e79d6af9ba..4b181969c432 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 @@ unfreeze: 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 = { -- cgit v1.2.3