idpf: fix idpf_vport_splitq_napi_poll()

idpf_vport_splitq_napi_poll() can incorrectly return @budget
after napi_complete_done() has been called.

This violates NAPI rules, because after napi_complete_done(),
current thread lost napi ownership.

Move the test against POLL_MODE before the napi_complete_done().

Fixes: c2d548cad150 ("idpf: add TX splitq napi poll support")
Reported-by: Peter Newman <peternewman@google.com>
Closes: https://lore.kernel.org/netdev/20250520121908.1805732-1-edumazet@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Joshua Hay <joshua.a.hay@intel.com>
Cc: Alan Brady <alan.brady@intel.com>
Cc: Madhu Chittim <madhu.chittim@intel.com>
Cc: Phani Burra <phani.r.burra@intel.com>
Cc: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
Link: https://patch.msgid.link/20250520124030.1983936-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index bdf52cef3891b8ff1d919b7024d42d024299215e..2d5f5c9f91ce1ef331e577848d91b0d130dcce8c 100644 (file)
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -4025,6 +4025,14 @@ static int idpf_vport_splitq_napi_poll(struct napi_struct *napi, int budget)
                return budget;
        }
 
+       /* Switch to poll mode in the tear-down path after sending disable
+        * queues virtchnl message, as the interrupts will be disabled after
+        * that.
+        */
+       if (unlikely(q_vector->num_txq && idpf_queue_has(POLL_MODE,
+                                                        q_vector->tx[0])))
+               return budget;
+
        work_done = min_t(int, work_done, budget - 1);
 
        /* Exit the polling mode, but don't re-enable interrupts if stack might
@@ -4035,15 +4043,7 @@ static int idpf_vport_splitq_napi_poll(struct napi_struct *napi, int budget)
        else
                idpf_vport_intr_set_wb_on_itr(q_vector);
 
-       /* Switch to poll mode in the tear-down path after sending disable
-        * queues virtchnl message, as the interrupts will be disabled after
-        * that
-        */
-       if (unlikely(q_vector->num_txq && idpf_queue_has(POLL_MODE,
-                                                        q_vector->tx[0])))
-               return budget;
-       else
-               return work_done;
+       return work_done;
 }
 
 /**