On 05/14/2013 05:32 PM, Or Gerlitz wrote:
> On Tue, May 14, 2013 at 6:26 PM, Alexander Duyck
> <alexander.h.duyck@xxxxxxxxx> wrote:
>>
>> This change is meant to fix a deadlock seen when pci_enable_sriov was
>> called from within a driver's probe routine. The issue was that
>> work_on_cpu calls flush_work which attempts to flush a work queue for a
>> cpu that we are currently working in. In order to avoid the reentrant
>> path we just skip the call to work_on_cpu in the case that the device
>> node matches our current node.
>>
>> Reported-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>> Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
>> ---
>>
>> This patch is meant to address the issue pointed out in an earlier patch
>> sent by Yinghai Lu titled:
>> [PATCH 6/7] PCI: Make sure VF's driver get attached after PF's
>>
>> drivers/pci/pci-driver.c | 14 +++++++++-----
>> 1 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
>> index 79277fb..caeb1c0 100644
>> --- a/drivers/pci/pci-driver.c
>> +++ b/drivers/pci/pci-driver.c
>> @@ -277,12 +277,16 @@ static int pci_call_probe(struct pci_driver *drv,
>> struct pci_dev *dev,
>> int error, node;
>> struct drv_dev_and_id ddi = { drv, dev, id };
>>
>> - /* Execute driver initialization on node where the device's
>> - bus is attached to. This way the driver likely allocates
>> - its local memory on the right node without any need to
>> - change it. */
>> + /*
>> + * Execute driver initialization on the node where the device's
>> + * bus is attached. This way the driver likely allocates
>> + * its local memory on the right node without any need to
>> + * change it. If the node is the current node just call
>> + * local_pci_probe and avoid the possibility of reentrant
>> + * calls to work_on_cpu.
>> + */
>> node = dev_to_node(&dev->dev);
>> - if (node >= 0) {
>> + if ((node >= 0) && (node != numa_node_id())) {
>> int cpu;
>>
>> get_online_cpus();
>
>
> Alex, FWIW a similar patch was posted by Michael during the last rc
> cycles of 3.9 see
> http://marc.info/?l=linux-netdev&m=136569426119644&w=2
Did his patch ever get applied anywhere? I don't see it in any of the
trees.
The advantage this approach has over the one in the similar patch is
that this covers a broader set of CPUs since anything on the same node
is local versus just the first CPU in a given NUMA node.
Thanks,
Alex
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