Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Yinghai Lu <yinghai@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Vinod Koul <vinod.koul@intel.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Len Brown <lenb@kernel.org>, Ashok Raj <ashok.raj@intel.com>,
	Yijing Wang <wangyijing@huawei.com>,
	Tony Luck <tony.luck@intel.com>,
	iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
	linux-acpi@vger.kernel.org
Subject: Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug
Date: Tue, 22 Apr 2014 11:49:48 +0200	[thread overview]
Message-ID: <2370777.I1hYvaFUEg@vostro.rjw.lan> (raw)
In-Reply-To: <1398150453-28141-18-git-send-email-jiang.liu@linux.intel.com>

On Tuesday, April 22, 2014 03:07:28 PM Jiang Liu wrote:
> Finally enhance pci_root driver to support DMAR device hotplug when
> hot-plugging PCI host bridges.
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
>  drivers/acpi/pci_root.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d388f13d48b4..aa8f549869f3 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -33,6 +33,7 @@
>  #include <linux/pci.h>
>  #include <linux/pci-acpi.h>
>  #include <linux/pci-aspm.h>
> +#include <linux/dmar.h>
>  #include <linux/acpi.h>
>  #include <linux/slab.h>
>  #include <acpi/apei.h>	/* for acpi_hest_init() */
> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	struct acpi_pci_root *root;
>  	acpi_handle handle = device->handle;
>  	int no_aspm = 0, clear_aspm = 0;
> +	bool hotadd = (system_state != SYSTEM_BOOTING);

The parens are not necessary in the above instruction.

>  	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
>  	if (!root)
> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
>  	device->driver_data = root;
>  
> +	if (hotadd && dmar_device_hotplug(handle, true)) {
> +		result = -ENXIO;
> +		goto end;
> +	}
> +
>  	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
>  	       acpi_device_name(device), acpi_device_bid(device),
>  	       root->segment, &root->secondary);
> @@ -583,7 +590,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  			root->segment, (unsigned int)root->secondary.start);
>  		device->driver_data = NULL;
>  		result = -ENODEV;
> -		goto end;
> +		goto remove_dmar;
>  	}
>  
>  	if (clear_aspm) {
> @@ -597,7 +604,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	if (device->wakeup.flags.run_wake)
>  		device_set_run_wake(root->bus->bridge, true);
>  
> -	if (system_state != SYSTEM_BOOTING) {
> +	if (hotadd) {
>  		pcibios_resource_survey_bus(root->bus);
>  		pci_assign_unassigned_root_bus_resources(root->bus);
>  	}
> @@ -607,6 +614,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	pci_unlock_rescan_remove();
>  	return 1;
>  
> +remove_dmar:
> +	if (hotadd)
> +		dmar_device_hotplug(handle, false);

I suppose that works if dmar_device_hotplug() returned false before?

>  end:
>  	kfree(root);
>  	return result;
> @@ -625,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>  
>  	pci_remove_root_bus(root->bus);
>  
> +	dmar_device_hotplug(device->handle, false);
> +
>  	pci_unlock_rescan_remove();
>  
>  	kfree(root);
> 

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