Re: [Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list

[David Vrabel <david.vrabel@citrix.com>]

On 22/09/16 22:02, Boris Ostrovsky wrote:
> On 09/22/2016 04:45 AM, Juergen Gross wrote:
>> The Xen pciback driver has a list of all pci devices it is ready to
>> seize. There is no check whether a to be added entry already exists.
>> While this might be no problem in the common case it might confuse
>> those which consume the list via sysfs.
>>
>> Modify the handling of this list by not adding an entry which already
>> exists. As this will be needed later split out the list handling into
>> a separate function.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>>  drivers/xen/xen-pciback/pci_stub.c | 39 ++++++++++++++++++++++++++++++--------
>>  1 file changed, 31 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
>> index 79a9e4d..0179333 100644
>> --- a/drivers/xen/xen-pciback/pci_stub.c
>> +++ b/drivers/xen/xen-pciback/pci_stub.c
>> @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void)
>>  	return 0;
>>  }
>>  
>> +static void pcistub_device_id_add_list(struct pcistub_device_id *new,
>> +				       int domain, int bus, unsigned int devfn)

I think this should allocate the new pcistub_device_id if needed.  You
can pass in GFP flags if needed.

Then it can return the newly allocated one, or the existing one.

static struct pcistub_device_id *pcistub_device_id_add_list(
    int domain, int bus, unsigned int devfn)

David