linux-kernel - Re: [Update][PATCH 4/5][RFT] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify

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Date:	Fri, 31 Jan 2014 17:28:36 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Aaron Lu <aaron.lu@...el.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>
Subject: Re: [Update][PATCH 4/5][RFT] ACPI / hotplug / PCI: Simplify
 acpi_install_hotplug_notify_handler()

On Wed, Jan 29, 2014 at 01:00:57AM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Use the observation that the ACPI scan handler of the device object
> in acpi_hotplug_notify_cb() can be obtained from that device object's
> handler pointer and do not pass it as data to
> acpi_install_hotplug_notify_handler() in acpi_scan_init_hotplug().
> 
> That allows the second argument of acpi_install_hotplug_notify_handler()
> to be dropped, so do it and update its callers accordingly.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/acpi/scan.c                |   31 ++++++++++++++++++-------------
>  drivers/pci/hotplug/acpiphp_glue.c |    2 +-
>  include/acpi/acpi_bus.h            |    2 +-
>  3 files changed, 20 insertions(+), 15 deletions(-)
> 
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -487,7 +487,6 @@ static void acpi_device_hotplug(void *da
>  
>  static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
>  {
> -	struct acpi_scan_handler *handler = data;
>  	u32 ost_code = ACPI_OST_SC_SUCCESS;
>  	struct acpi_device *adev;
>  	acpi_status status;
> @@ -503,13 +502,6 @@ static void acpi_hotplug_notify_cb(acpi_
>  
>  	case ACPI_NOTIFY_EJECT_REQUEST:
>  		acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
> -		if (handler && !handler->hotplug.enabled) {
> -			acpi_handle_err(handle, "Eject disabled\n");
> -			ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> -			goto out;
> -		}
> -		acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
> -					  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
>  		break;
>  
>  	case ACPI_NOTIFY_DEVICE_WAKE:
> @@ -535,11 +527,24 @@ static void acpi_hotplug_notify_cb(acpi_
>  		goto out;
>  	}
>  
> +	mutex_lock(&acpi_scan_lock);

This is weird. I'm testing against your test-next branch which has this
patch included. If I remove locking here, TBT hotplug works fine. Otherwise
I can see the first hotplug/unplug works but after that I cannot get any
events anymore.

>  	ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
> -	if (acpi_bus_get_device(handle, &adev))
> +	if (acpi_bus_get_device(handle, &adev)) {
> +		mutex_unlock(&acpi_scan_lock);
>  		goto out;
> -
> +	}
> +	if (type == ACPI_NOTIFY_EJECT_REQUEST) {
> +		if (adev->handler && !adev->handler->hotplug.enabled) {
> +			acpi_handle_err(handle, "Eject disabled\n");
> +			ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> +			mutex_unlock(&acpi_scan_lock);
> +			goto out;
> +		}
> +		acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
> +					  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
> +	}
>  	get_device(&adev->dev);
> +	mutex_unlock(&acpi_scan_lock);
>  	status = acpi_hotplug_execute(acpi_device_hotplug, adev, type);
>  	if (ACPI_SUCCESS(status))
>  		return;
--
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