Re: [Intel-wired-lan] [PATCH net] igc: remove napi_synchronize() in igc_down()

On 20/07/2026 10:39, Ruinskiy, Dima wrote:
> On 13/07/2026 12:42, Maciej Fijalkowski wrote:
>> On Sun, Jul 12, 2026 at 02:22:42PM +0100, David Carlier wrote:
>>> When an AF_XDP zero-copy application is killed abruptly, the XSK pool is
>>> torn down but NAPI keeps polling. igc_clean_rx_irq_zc() then returns the
>>> full budget on every poll, so napi_complete_done() never clears
>>> NAPI_STATE_SCHED.
>>>
>>> igc_down() calls napi_synchronize() before napi_disable(), so it spins
>>> forever waiting for that bit and the interface never goes down. Drop the
>>> napi_synchronize() and let napi_disable() do the job -- it sets
>>> NAPI_STATE_DISABLE, which forces the stuck poll to complete. Reorder it
>>> ahead of igc_set_queue_napi() so the NAPI mapping is cleared only after
>>> polling has stopped, matching the recent igb fix b1e067240379.
>>>
>>> Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
>>> Suggested-by: Maciej Fijalkowski <[email protected]>
>>> Cc: [email protected]
>>> Signed-off-by: David Carlier <[email protected]>
>>
>> Reviewed-by: Maciej Fijalkowski <[email protected]>
>>
>> This is a mirror of what Alex Dvoretsky did on igb, correct? Did you
>> reproduce the same issue on your side or is it a blind shot at this
>> driver?
>>
>> Regardless, I think it's a correct thing to do, but some clarification
>> would be nice.
>>
>>> ---
>>>   drivers/net/ethernet/intel/igc/igc_main.c | 3 +--
>>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ 
>>> ethernet/intel/igc/igc_main.c
>>> index 2c9e2dfd8499..b3883a5a7d7a 100644
>>> --- a/drivers/net/ethernet/intel/igc/igc_main.c
>>> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
>>> @@ -5352,9 +5352,8 @@ void igc_down(struct igc_adapter *adapter)
>>>       for (i = 0; i < adapter->num_q_vectors; i++) {
>>>           if (adapter->q_vector[i]) {
>>> -            napi_synchronize(&adapter->q_vector[i]->napi);
>>> -            igc_set_queue_napi(adapter, i, NULL);
>>>               napi_disable(&adapter->q_vector[i]->napi);
>>> +            igc_set_queue_napi(adapter, i, NULL);
>>>           }
>>>       }
>>> -- 
>>> 2.53.0
>>>
> Reviewed-by: Dima Ruinskiy <[email protected]>
Tested-by: Moriya Kadosh <[email protected]>