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Message-ID: <20170614180943.GA20778@bhelgaas-glaptop.roam.corp.google.com>
Date: Wed, 14 Jun 2017 13:09:43 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Linux ACPI <linux-acpi@...r.kernel.org>,
Linux PCI <linux-pci@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
LKML <linux-kernel@...r.kernel.org>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Linux USB <linux-usb@...r.kernel.org>,
Mathias Nyman <mathias.nyman@...ux.intel.com>,
Felipe Balbi <balbi@...nel.org>,
Mario Limonciello <mario_limonciello@...l.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Dominik Brodowski <linux@...inikbrodowski.net>,
Hans De Goede <hdegoede@...hat.com>,
Alan Stern <stern@...land.harvard.edu>
Subject: Re: [PATCH v2 1/8] ACPI / PM: Run wakeup notify handlers
synchronously
On Mon, Jun 12, 2017 at 10:48:41PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> The work functions provided by the users of acpi_add_pm_notifier()
> should be run synchronously before re-enabling the wakeup GPE in
> case they are used to clear the status and/or disable the wakeup
> signaling at the source. Otherwise, which is the case currently in
> the PCI bus type code, the same wakeup event may be signaled for
> multiple times while the execution of the work function in response
> to it has already been queued up.
>
> Fortunately, acpi_add_pm_notifier() is only used by PCI and by
> ACPI device PM code internally, so the change is relatively
> straightforward to make.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
> drivers/acpi/device_pm.c | 27 +++++++++++----------------
> drivers/pci/pci-acpi.c | 17 +++++++----------
> include/acpi/acpi_bus.h | 4 ++--
> 3 files changed, 20 insertions(+), 28 deletions(-)
>
> Index: linux-pm/drivers/acpi/device_pm.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/device_pm.c
> +++ linux-pm/drivers/acpi/device_pm.c
> @@ -400,8 +400,8 @@ static void acpi_pm_notify_handler(acpi_
>
> if (adev->wakeup.flags.notifier_present) {
> __pm_wakeup_event(adev->wakeup.ws, 0);
> - if (adev->wakeup.context.work.func)
> - queue_pm_work(&adev->wakeup.context.work);
> + if (adev->wakeup.context.func)
> + adev->wakeup.context.func(&adev->wakeup.context);
> }
>
> mutex_unlock(&acpi_pm_notifier_lock);
> @@ -413,7 +413,7 @@ static void acpi_pm_notify_handler(acpi_
> * acpi_add_pm_notifier - Register PM notify handler for given ACPI device.
> * @adev: ACPI device to add the notify handler for.
> * @dev: Device to generate a wakeup event for while handling the notification.
> - * @work_func: Work function to execute when handling the notification.
> + * @func: Work function to execute when handling the notification.
> *
> * NOTE: @adev need not be a run-wake or wakeup device to be a valid source of
> * PM wakeup events. For example, wakeup events may be generated for bridges
> @@ -421,11 +421,11 @@ static void acpi_pm_notify_handler(acpi_
> * bridge itself doesn't have a wakeup GPE associated with it.
> */
> acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
> - void (*work_func)(struct work_struct *work))
> + void (*func)(struct acpi_device_wakeup_context *context))
> {
> acpi_status status = AE_ALREADY_EXISTS;
>
> - if (!dev && !work_func)
> + if (!dev && !func)
> return AE_BAD_PARAMETER;
>
> mutex_lock(&acpi_pm_notifier_lock);
> @@ -435,8 +435,7 @@ acpi_status acpi_add_pm_notifier(struct
>
> adev->wakeup.ws = wakeup_source_register(dev_name(&adev->dev));
> adev->wakeup.context.dev = dev;
> - if (work_func)
> - INIT_WORK(&adev->wakeup.context.work, work_func);
> + adev->wakeup.context.func = func;
>
> status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
> acpi_pm_notify_handler, NULL);
> @@ -469,10 +468,7 @@ acpi_status acpi_remove_pm_notifier(stru
> if (ACPI_FAILURE(status))
> goto out;
>
> - if (adev->wakeup.context.work.func) {
> - cancel_work_sync(&adev->wakeup.context.work);
> - adev->wakeup.context.work.func = NULL;
> - }
> + adev->wakeup.context.func = NULL;
> adev->wakeup.context.dev = NULL;
> wakeup_source_unregister(adev->wakeup.ws);
>
> @@ -658,16 +654,15 @@ EXPORT_SYMBOL(acpi_pm_device_sleep_state
>
> /**
> * acpi_pm_notify_work_func - ACPI devices wakeup notification work function.
> - * @work: Work item to handle.
> + * @context: Device wakeup context.
> */
> -static void acpi_pm_notify_work_func(struct work_struct *work)
> +static void acpi_pm_notify_work_func(struct acpi_device_wakeup_context *context)
> {
> - struct device *dev;
> + struct device *dev = context->dev;
>
> - dev = container_of(work, struct acpi_device_wakeup_context, work)->dev;
> if (dev) {
> pm_wakeup_event(dev, 0);
> - pm_runtime_resume(dev);
> + pm_request_resume(dev);
> }
> }
>
> Index: linux-pm/include/acpi/acpi_bus.h
> ===================================================================
> --- linux-pm.orig/include/acpi/acpi_bus.h
> +++ linux-pm/include/acpi/acpi_bus.h
> @@ -319,7 +319,7 @@ struct acpi_device_wakeup_flags {
> };
>
> struct acpi_device_wakeup_context {
> - struct work_struct work;
> + void (*func)(struct acpi_device_wakeup_context *context);
> struct device *dev;
> };
>
> @@ -599,7 +599,7 @@ static inline bool acpi_device_always_pr
>
> #ifdef CONFIG_PM
> acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
> - void (*work_func)(struct work_struct *work));
> + void (*func)(struct acpi_device_wakeup_context *context));
> acpi_status acpi_remove_pm_notifier(struct acpi_device *adev);
> int acpi_pm_device_sleep_state(struct device *, int *, int);
> int acpi_pm_device_run_wake(struct device *, bool);
> Index: linux-pm/drivers/pci/pci-acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-acpi.c
> +++ linux-pm/drivers/pci/pci-acpi.c
> @@ -395,29 +395,26 @@ bool pciehp_is_native(struct pci_dev *pd
>
> /**
> * pci_acpi_wake_bus - Root bus wakeup notification fork function.
> - * @work: Work item to handle.
> + * @context: Device wakeup context.
> */
> -static void pci_acpi_wake_bus(struct work_struct *work)
> +static void pci_acpi_wake_bus(struct acpi_device_wakeup_context *context)
> {
> struct acpi_device *adev;
> struct acpi_pci_root *root;
>
> - adev = container_of(work, struct acpi_device, wakeup.context.work);
> + adev = container_of(context, struct acpi_device, wakeup.context);
> root = acpi_driver_data(adev);
> pci_pme_wakeup_bus(root->bus);
> }
>
> /**
> * pci_acpi_wake_dev - PCI device wakeup notification work function.
> - * @handle: ACPI handle of a device the notification is for.
> - * @work: Work item to handle.
> + * @context: Device wakeup context.
> */
> -static void pci_acpi_wake_dev(struct work_struct *work)
> +static void pci_acpi_wake_dev(struct acpi_device_wakeup_context *context)
> {
> - struct acpi_device_wakeup_context *context;
> struct pci_dev *pci_dev;
>
> - context = container_of(work, struct acpi_device_wakeup_context, work);
> pci_dev = to_pci_dev(context->dev);
>
> if (pci_dev->pme_poll)
> @@ -425,7 +422,7 @@ static void pci_acpi_wake_dev(struct wor
>
> if (pci_dev->current_state == PCI_D3cold) {
> pci_wakeup_event(pci_dev);
> - pm_runtime_resume(&pci_dev->dev);
> + pm_request_resume(&pci_dev->dev);
> return;
> }
>
> @@ -434,7 +431,7 @@ static void pci_acpi_wake_dev(struct wor
> pci_check_pme_status(pci_dev);
>
> pci_wakeup_event(pci_dev);
> - pm_runtime_resume(&pci_dev->dev);
> + pm_request_resume(&pci_dev->dev);
>
> pci_pme_wakeup_bus(pci_dev->subordinate);
> }
>
> --
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