From: Alexander Duyck Date: Mon, 20 Mar 2017 14:43:02 -0700 Subject: [Intel-wired-lan] [net PATCH] i40e: Do not enable NAPI on q_vectors that have no rings Message-ID: <20170320213859.13451.3294.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: From: Alexander Duyck When testing the epoll w/ busy poll code I found that I could get into a state where the i40e driver had q_vectors w/ active NAPI that had no rings. This was resulting in a divide by zero error. To correct it I am updating the driver code so that we only support NAPI on q_vectors that have 1 or more rings allocated to them. Signed-off-by: Alexander Duyck --- I am submitting this for net, not next-queue since this fixes an issue that can result in a kernel panic using existing kernel interfaces. Testing Hints: I found the issue this fixes while using sockperf with busy poll. Basically all I did is run a test with sockperf in which busy polling was running, stopped the test, changed the number of queues via "ethtool -L" and the system generated a divide by 0 error. drivers/net/ethernet/intel/i40e/i40e_main.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 9df0d86812e7..1e12248a34ba 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -4440,8 +4440,12 @@ static void i40e_napi_enable_all(struct i40e_vsi *vsi) if (!vsi->netdev) return; - for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) - napi_enable(&vsi->q_vectors[q_idx]->napi); + for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) { + struct i40e_q_vector *q_vector = vsi->q_vectors[q_idx]; + + if (q_vector->rx.ring || q_vector->tx.ring) + napi_enable(&q_vector->napi); + } } /** @@ -4455,8 +4459,12 @@ static void i40e_napi_disable_all(struct i40e_vsi *vsi) if (!vsi->netdev) return; - for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) - napi_disable(&vsi->q_vectors[q_idx]->napi); + for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) { + struct i40e_q_vector *q_vector = vsi->q_vectors[q_idx]; + + if (q_vector->rx.ring || q_vector->tx.ring) + napi_disable(&q_vector->napi); + } } /**