linux-kernel - Re: [PATCH v8 09/22] PCI, ACPI: Add pci_root

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Message-ID: <2032314.LPbgrOarU3@vostro.rjw.lan>
Date:	Sun, 13 Jan 2013 00:26:08 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>, Len Brown <lenb@...nel.org>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	Jiang Liu <jiang.liu@...wei.com>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v8 09/22] PCI, ACPI: Add pci_root_hp hot removal notification support.

On Friday, January 11, 2013 02:40:36 PM Yinghai Lu wrote:
> Add missing hot_remove support for root device.
> 
> How to test it?
> Find out root bus number to acpi root name mapping from dmesg or /sys
> 
>   echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify
> to remove root bus
> 
> -v2: separate stop and remove, so it will be safe for comingi
> 	acpi_pci_bind_notify() changes.
> 
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Cc: Len Brown <lenb@...nel.org>
> Cc: linux-acpi@...r.kernel.org
> ---
>  drivers/acpi/pci_root.c |   67 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 67 insertions(+)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 5c1f462c..5ae36d8 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -740,6 +740,12 @@ static void add_acpi_root_bridge(acpi_handle handle)
>  	list_add(&bridge->list, &acpi_root_bridge_list);
>  }
>  
> +static void remove_acpi_root_bridge(struct acpi_root_bridge *bridge)
> +{
> +	list_del(&bridge->list);
> +	kfree(bridge);
> +}
> +
>  struct acpi_root_hp_work {
>  	struct work_struct work;
>  	acpi_handle handle;
> @@ -800,6 +806,61 @@ static void handle_root_bridge_insertion(acpi_handle handle)
>  		printk(KERN_ERR "cannot add bridge to acpi list\n");
>  }
>  
> +static int acpi_root_evaluate_object(acpi_handle handle, char *cmd, int val)
> +{
> +	acpi_status status;
> +	struct acpi_object_list arg_list;
> +	union acpi_object arg;
> +
> +	arg_list.count = 1;
> +	arg_list.pointer = &arg;
> +	arg.type = ACPI_TYPE_INTEGER;
> +	arg.integer.value = val;
> +
> +	status = acpi_evaluate_object(handle, cmd, &arg_list, NULL);
> +	if (ACPI_FAILURE(status)) {
> +		pr_warn("%s: %s to %d failed\n",
> +				 __func__, cmd, val);
> +		return -1;

Please use a meaningful error code.

> +	}
> +
> +	return 0;
> +}
> +
> +static void handle_root_bridge_removal(acpi_handle handle,
> +		 struct acpi_root_bridge *bridge)
> +{
> +	u32 flags = 0;
> +	struct acpi_device *device;
> +
> +	if (bridge) {
> +		flags = bridge->flags;
> +		remove_acpi_root_bridge(bridge);
> +	}
> +
> +	if (!acpi_bus_get_device(handle, &device)) {
> +		int ret_val;
> +
> +		/* remove pci devices at first */
> +		ret_val = acpi_bus_trim(device, 0);
> +		printk(KERN_DEBUG "acpi_bus_trim stop return %x\n", ret_val);
> +
> +		/* remove acpi devices */
> +		ret_val = acpi_bus_trim(device, 1);
> +		printk(KERN_DEBUG "acpi_bus_trim remove return %x\n", ret_val);

First of all, I don't agree with the way acpi_bus_trim() is used here, as
I said in the previous message.

Second, this code duplicates the code you're adding on [08/22] almost exactly.
Please put it into a one separate function instead of duplicating it like this.

> +	}
> +
> +	if (flags & ROOT_BRIDGE_HAS_PS3) {
> +		acpi_status status;
> +
> +		status = acpi_evaluate_object(handle, "_PS3", NULL, NULL);
> +		if (ACPI_FAILURE(status))
> +			pr_warn("%s: _PS3 failed\n", __func__);

No, please.  acpi_device_set_power() is for that.

> +	}
> +	if (flags & ROOT_BRIDGE_HAS_EJ0)
> +		acpi_root_evaluate_object(handle, "_EJ0", 1);

That seems to duplicate some code from scan.c.

> +}
> +
>  static void _handle_hotplug_event_root(struct work_struct *work)
>  {
>  	struct acpi_root_bridge *bridge;
> @@ -840,6 +901,12 @@ static void _handle_hotplug_event_root(struct work_struct *work)
>  		}
>  		break;
>  
> +	case ACPI_NOTIFY_EJECT_REQUEST:
> +		/* request device eject */
> +		printk(KERN_DEBUG "%s: Device eject notify on %s\n", __func__,
> +				 objname);
> +		handle_root_bridge_removal(handle, bridge);
> +		break;
>  	default:
>  		printk(KERN_WARNING "notify_handler: unknown event type 0x%x for %s\n",
>  				 type, objname);
> 

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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