net: provide generic busy polling to all NAPI drivers
NAPI drivers no longer need to observe a particular protocol
to benefit from busy polling (CONFIG_NET_RX_BUSY_POLL=y)
napi_hash_add() and napi_hash_del() are automatically called
from core networking stack, respectively from
netif_napi_add() and netif_napi_del()
This patch depends on free_netdev() and netif_napi_del() being
called from process context, which seems to be the norm.
Drivers might still prefer to call napi_hash_del() on their
own, since they might combine all the rcu grace periods into
a single one, knowing their NAPI structures lifetime, while
core networking stack has no idea of a possible combining.
Once this patch proves to not bring serious regressions,
we will cleanup drivers to either remove napi_hash_del()
or provide appropriate rcu grace periods combining.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index ab92229..d9add7c 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -46,7 +46,6 @@
for_each_rx_queue_cnic(bp, i) {
netif_napi_add(bp->dev, &bnx2x_fp(bp, i, napi),
bnx2x_poll, NAPI_POLL_WEIGHT);
- napi_hash_add(&bnx2x_fp(bp, i, napi));
}
}
@@ -58,7 +57,6 @@
for_each_eth_queue(bp, i) {
netif_napi_add(bp->dev, &bnx2x_fp(bp, i, napi),
bnx2x_poll, NAPI_POLL_WEIGHT);
- napi_hash_add(&bnx2x_fp(bp, i, napi));
}
}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index db15c5e..f2d0dc9 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -4227,12 +4227,10 @@
bnapi = bp->bnapi[i];
netif_napi_add(bp->dev, &bnapi->napi,
bnxt_poll, 64);
- napi_hash_add(&bnapi->napi);
}
} else {
bnapi = bp->bnapi[0];
netif_napi_add(bp->dev, &bnapi->napi, bnxt_poll, 64);
- napi_hash_add(&bnapi->napi);
}
}
diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index f650f29..48d8fbb 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -2527,7 +2527,6 @@
goto err;
netif_napi_add(dev, &iq->napi, napi_rx_handler, 64);
- napi_hash_add(&iq->napi);
iq->cur_desc = iq->desc;
iq->cidx = 0;
iq->gen = 1;
diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index b36643e..b2182d3 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -2458,13 +2458,11 @@
switch (vnic_dev_get_intr_mode(enic->vdev)) {
default:
netif_napi_add(netdev, &enic->napi[0], enic_poll, 64);
- napi_hash_add(&enic->napi[0]);
break;
case VNIC_DEV_INTR_MODE_MSIX:
for (i = 0; i < enic->rq_count; i++) {
netif_napi_add(netdev, &enic->napi[i],
enic_poll_msix_rq, NAPI_POLL_WEIGHT);
- napi_hash_add(&enic->napi[i]);
}
for (i = 0; i < enic->wq_count; i++)
netif_napi_add(netdev, &enic->napi[enic_cq_wq(enic, i)],
diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index c29d624..4cab887 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -2630,7 +2630,6 @@
eqo->affinity_mask);
netif_napi_add(adapter->netdev, &eqo->napi, be_poll,
BE_NAPI_WEIGHT);
- napi_hash_add(&eqo->napi);
}
return 0;
}
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index f3168bc..e771e76 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -844,7 +844,6 @@
/* initialize NAPI */
netif_napi_add(adapter->netdev, &q_vector->napi,
ixgbe_poll, 64);
- napi_hash_add(&q_vector->napi);
#ifdef CONFIG_NET_RX_BUSY_POLL
/* initialize busy poll */
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 592ff23..2955186 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -2483,9 +2483,6 @@
q_vector->v_idx = q_idx;
netif_napi_add(adapter->netdev, &q_vector->napi,
ixgbevf_poll, 64);
-#ifdef CONFIG_NET_RX_BUSY_POLL
- napi_hash_add(&q_vector->napi);
-#endif
adapter->q_vector[q_idx] = q_vector;
}
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 3a6176f..af975a2 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -155,13 +155,11 @@
cq->mcq.comp = cq->is_tx ? mlx4_en_tx_irq : mlx4_en_rx_irq;
cq->mcq.event = mlx4_en_cq_event;
- if (cq->is_tx) {
+ if (cq->is_tx)
netif_tx_napi_add(cq->dev, &cq->napi, mlx4_en_poll_tx_cq,
NAPI_POLL_WEIGHT);
- } else {
+ else
netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_rx_cq, 64);
- napi_hash_add(&cq->napi);
- }
napi_enable(&cq->napi);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index ffb1f9c..f6a8cc7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -982,7 +982,6 @@
mlx5e_build_channeltc_to_txq_map(priv, ix);
netif_napi_add(netdev, &c->napi, mlx5e_napi_poll, 64);
- napi_hash_add(&c->napi);
err = mlx5e_open_tx_cqs(c, cparam);
if (err)
diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index acf8661..270c9ee 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -3814,7 +3814,6 @@
ss->dev = mgp->dev;
netif_napi_add(ss->dev, &ss->napi, myri10ge_poll,
myri10ge_napi_weight);
- napi_hash_add(&ss->napi);
}
return 0;
abort:
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index a3c42a3..4e82bcf 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -2059,7 +2059,6 @@
channel->napi_dev = efx->net_dev;
netif_napi_add(channel->napi_dev, &channel->napi_str,
efx_poll, napi_weight);
- napi_hash_add(&channel->napi_str);
efx_channel_busy_poll_init(channel);
}
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d1d14ce..b1ae4cb 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1610,7 +1610,6 @@
vi->rq[i].pages = NULL;
netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
napi_weight);
- napi_hash_add(&vi->rq[i].napi);
sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e5c33b2..7d2d1d7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -466,6 +466,9 @@
* @napi: napi context
*
* generate a new napi_id and store a @napi under it in napi_hash
+ * Used for busy polling (CONFIG_NET_RX_BUSY_POLL)
+ * Note: This is normally automatically done from netif_napi_add(),
+ * so might disappear in a future linux version.
*/
void napi_hash_add(struct napi_struct *napi);
@@ -476,6 +479,10 @@
* Warning: caller must observe rcu grace period
* before freeing memory containing @napi, if
* this function returns true.
+ * Note: core networking stack automatically calls it
+ * from netif_napi_del()
+ * Drivers might want to call this helper to combine all
+ * the needed rcu grace periods into a single one.
*/
bool napi_hash_del(struct napi_struct *napi);
diff --git a/net/core/dev.c b/net/core/dev.c
index 59dddac..41cef3e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4807,6 +4807,7 @@
napi->poll_owner = -1;
#endif
set_bit(NAPI_STATE_SCHED, &napi->state);
+ napi_hash_add(napi);
}
EXPORT_SYMBOL(netif_napi_add);
@@ -4826,8 +4827,12 @@
}
EXPORT_SYMBOL(napi_disable);
+/* Must be called in process context */
void netif_napi_del(struct napi_struct *napi)
{
+ might_sleep();
+ if (napi_hash_del(napi))
+ synchronize_net();
list_del_init(&napi->dev_list);
napi_free_frags(napi);
@@ -7227,11 +7232,13 @@
* This function does the last stage of destroying an allocated device
* interface. The reference to the device object is released.
* If this is the last reference then it will be freed.
+ * Must be called in process context.
*/
void free_netdev(struct net_device *dev)
{
struct napi_struct *p, *n;
+ might_sleep();
netif_free_tx_queues(dev);
#ifdef CONFIG_SYSFS
kvfree(dev->_rx);