Re: [PATCH v3, part2 17/20] PCI, iommu: use hotplug-safe iterators to walk PCI buses

[Don Dutile <ddutile@redhat.com>]

On 06/17/2013 04:20 PM, Bjorn Helgaas wrote:
> On Sun, May 26, 2013 at 11:53:14PM +0800, Jiang Liu wrote:
>> Enhance iommu drviers to use hotplug-safe iterators to walk
>> PCI buses.
>>
>> Signed-off-by: Jiang Liu<jiang.liu@huawei.com>
>> Cc: Joerg Roedel<joro@8bytes.org>
>> Cc: Ingo Molnar<mingo@kernel.org>
>> Cc: Donald Dutile<ddutile@redhat.com>
>> Cc: Hannes Reinecke<hare@suse.de>
>> Cc: "Li, Zhen-Hua"<zhen-hual@hp.com>
>> Cc: iommu@lists.linux-foundation.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>>   drivers/iommu/amd_iommu.c | 4 +++-
>>   drivers/iommu/dmar.c      | 6 ++++--
>
> The AMD and Intel IOMMU drivers are very different, and I would
> split this into a patch for each.
>
+1

>>   2 files changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>> index 21d02b0..eef7a7e 100644
>> --- a/drivers/iommu/amd_iommu.c
>> +++ b/drivers/iommu/amd_iommu.c
>> @@ -352,6 +352,7 @@ static int init_iommu_group(struct device *dev)
>>   	struct iommu_dev_data *dev_data;
>>   	struct iommu_group *group;
>>   	struct pci_dev *dma_pdev;
>> +	struct pci_bus *b = NULL;
>>   	int ret;
>>
>>   	group = iommu_group_get(dev);
>> @@ -388,7 +389,7 @@ static int init_iommu_group(struct device *dev)
>>   		 * the alias.  Be careful to also test the parent device if
>>   		 * we think the alias is the root of the group.
>>   		 */
>> -		bus = pci_find_bus(0, alias>>  8);
>> +		b = bus = pci_get_bus(0, alias>>  8);
>>   		if (!bus)
>>   			goto use_group;
>>
>> @@ -408,6 +409,7 @@ static int init_iommu_group(struct device *dev)
>>   	dma_pdev = get_isolation_root(pci_dev_get(to_pci_dev(dev)));
>>   use_pdev:
>>   	ret = use_pdev_iommu_group(dma_pdev, dev);
>> +	pci_bus_put(b);
>>   	pci_dev_put(dma_pdev);
>>   	return ret;
>>   use_group:
>> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
>> index a7967ce..7162787 100644
>> --- a/drivers/iommu/dmar.c
>> +++ b/drivers/iommu/dmar.c
>> @@ -67,12 +67,12 @@ static void __init dmar_register_drhd_unit(struct dmar_drhd_unit *drhd)
>>   static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
>>   					   struct pci_dev **dev, u16 segment)
>>   {
>> -	struct pci_bus *bus;
>> +	struct pci_bus *b, *bus;
>>   	struct pci_dev *pdev = NULL;
>>   	struct acpi_dmar_pci_path *path;
>>   	int count;
>>
>> -	bus = pci_find_bus(segment, scope->bus);
>> +	b = bus = pci_get_bus(segment, scope->bus);
>>   	path = (struct acpi_dmar_pci_path *)(scope + 1);
>>   	count = (scope->length - sizeof(struct acpi_dmar_device_scope))
>>   		/ sizeof(struct acpi_dmar_pci_path);
>> @@ -97,6 +97,8 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
>>   		count --;
>>   		bus = pdev->subordinate;
>>   	}
>> +	pci_bus_put(b);
>> +
>>   	if (!pdev) {
>>   		pr_warn("Device scope device [%04x:%02x:%02x.%02x] not found\n",
>>   			segment, scope->bus, path->dev, path->fn);
>> --
>> 1.8.1.2
>>