From: Tianyi Gao <tianyi@cloudflare.com>
To: netdev@vger.kernel.org
Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@kernel.org,
kuba@kernel.org, pabeni@redhat.com, toke@redhat.com,
lorenzo@kernel.org, horms@kernel.org, shuah@kernel.org,
ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
john.fastabend@gmail.com, sdf@fomichev.me, joe@dama.to,
linux-kselftest@vger.kernel.org, bpf@vger.kernel.org,
kernel-team@cloudflare.com, tianyi.gao@linux.dev,
Tianyi Gao <tianyi@cloudflare.com>
Subject: [PATCH net-next v3 1/5] veth: refactor NAPI enable paths
Date: Sun, 15 Nov 2026 19:35:27 +0000 [thread overview]
Message-ID: <20261115193531.57679-2-tianyi@cloudflare.com> (raw)
In-Reply-To: <20261115193531.57679-1-tianyi@cloudflare.com>
veth_enable_xdp_range() adds the NAPI instances itself, only to pass
rq->xdp_napi.napi_id as the napi_id argument of xdp_rxq_info_reg(). That
argument is unused in __xdp_rxq_info_reg() since commit 5ef44b3cb43b
("xsk: Bring back busy polling support"). Pass 0 instead, as ena, bnxt
and fec already do.
veth_enable_xdp_range() then no longer needs the NAPI instances. Move
netif_napi_add() from it and from veth_napi_enable_range() into
__veth_napi_enable_range(). Add the instances after the allocations
that can fail, and before the loop that enables them. Drop the
napi_already_on and delete_napi arguments.
veth_napi_enable_range() and veth_napi_enable() are then trivial
wrappers. Remove them, and rename __veth_napi_enable_range() and
__veth_napi_enable() to veth_napi_enable_range() and veth_napi_enable().
Signed-off-by: Tianyi Gao <tianyi@cloudflare.com>
---
Sashiko [1] pointed out that v2 added and enabled each NAPI instance in
the same loop, so a failed kthread creation could leave earlier instances
threaded and later ones not. v3 adds all instances before it enables any,
as the old code did, so such a failure turns off threaded mode for all.
[1] https://lore.kernel.org/all/179470883254.2199510.15270739408094114749@kernel.org/
---
drivers/net/veth.c | 82 +++++++++++-----------------------------------
1 file changed, 20 insertions(+), 62 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 0539b3661793..3cbedb8bad53 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1037,7 +1037,7 @@ static int veth_create_page_pool(struct veth_rq *rq)
return 0;
}
-static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
+static int veth_napi_enable_range(struct net_device *dev, int start, int end)
{
struct veth_priv *priv = netdev_priv(dev);
int err, i;
@@ -1056,6 +1056,9 @@ static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
goto err_xdp_ring;
}
+ for (i = start; i < end; i++)
+ netif_napi_add(dev, &priv->rq[i].xdp_napi, veth_poll);
+
for (i = start; i < end; i++) {
struct veth_rq *rq = &priv->rq[i];
@@ -1079,9 +1082,9 @@ static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
return err;
}
-static int __veth_napi_enable(struct net_device *dev)
+static int veth_napi_enable(struct net_device *dev)
{
- return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
+ return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
}
static void veth_napi_del_range(struct net_device *dev, int start, int end)
@@ -1122,8 +1125,7 @@ static bool veth_gro_requested(const struct net_device *dev)
return !!(dev->wanted_features & NETIF_F_GRO);
}
-static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
- bool napi_already_on)
+static int veth_enable_xdp_range(struct net_device *dev, int start, int end)
{
struct veth_priv *priv = netdev_priv(dev);
int err, i;
@@ -1131,9 +1133,7 @@ static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
for (i = start; i < end; i++) {
struct veth_rq *rq = &priv->rq[i];
- if (!napi_already_on)
- netif_napi_add(dev, &rq->xdp_napi, veth_poll);
- err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
+ err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, 0);
if (err < 0)
goto err_rxq_reg;
@@ -1151,21 +1151,13 @@ static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
err_reg_mem:
xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
err_rxq_reg:
- if (!napi_already_on)
- netif_napi_del(&priv->rq[i].xdp_napi);
- for (i--; i >= start; i--) {
- struct veth_rq *rq = &priv->rq[i];
-
- xdp_rxq_info_unreg(&rq->xdp_rxq);
- if (!napi_already_on)
- netif_napi_del(&rq->xdp_napi);
- }
+ for (i--; i >= start; i--)
+ xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
return err;
}
-static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
- bool delete_napi)
+static void veth_disable_xdp_range(struct net_device *dev, int start, int end)
{
struct veth_priv *priv = netdev_priv(dev);
int i;
@@ -1175,9 +1167,6 @@ static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
rq->xdp_rxq.mem = rq->xdp_mem;
xdp_rxq_info_unreg(&rq->xdp_rxq);
-
- if (delete_napi)
- netif_napi_del(&rq->xdp_napi);
}
}
@@ -1188,14 +1177,15 @@ static int veth_enable_xdp(struct net_device *dev)
int err, i;
if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
- err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
+ err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues);
if (err)
return err;
if (!napi_already_on) {
- err = __veth_napi_enable(dev);
+ err = veth_napi_enable(dev);
if (err) {
- veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
+ veth_disable_xdp_range(dev, 0,
+ dev->real_num_rx_queues);
return err;
}
}
@@ -1220,35 +1210,7 @@ static void veth_disable_xdp(struct net_device *dev)
if (!netif_running(dev) || !veth_gro_requested(dev))
veth_napi_del(dev);
- veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
-}
-
-static int veth_napi_enable_range(struct net_device *dev, int start, int end)
-{
- struct veth_priv *priv = netdev_priv(dev);
- int err, i;
-
- for (i = start; i < end; i++) {
- struct veth_rq *rq = &priv->rq[i];
-
- netif_napi_add(dev, &rq->xdp_napi, veth_poll);
- }
-
- err = __veth_napi_enable_range(dev, start, end);
- if (err) {
- for (i = start; i < end; i++) {
- struct veth_rq *rq = &priv->rq[i];
-
- netif_napi_del(&rq->xdp_napi);
- }
- return err;
- }
- return err;
-}
-
-static int veth_napi_enable(struct net_device *dev)
-{
- return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
+ veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues);
}
static void veth_disable_range_safe(struct net_device *dev, int start, int end)
@@ -1260,7 +1222,7 @@ static void veth_disable_range_safe(struct net_device *dev, int start, int end)
if (priv->_xdp_prog) {
veth_napi_del_range(dev, start, end);
- veth_disable_xdp_range(dev, start, end, false);
+ veth_disable_xdp_range(dev, start, end);
} else if (veth_gro_requested(dev)) {
veth_napi_del_range(dev, start, end);
}
@@ -1275,17 +1237,13 @@ static int veth_enable_range_safe(struct net_device *dev, int start, int end)
return 0;
if (priv->_xdp_prog) {
- /* these channels are freshly initialized, napi is not on there even
- * when GRO is requeste
- */
- err = veth_enable_xdp_range(dev, start, end, false);
+ err = veth_enable_xdp_range(dev, start, end);
if (err)
return err;
- err = __veth_napi_enable_range(dev, start, end);
+ err = veth_napi_enable_range(dev, start, end);
if (err) {
- /* on error always delete the newly added napis */
- veth_disable_xdp_range(dev, start, end, true);
+ veth_disable_xdp_range(dev, start, end);
return err;
}
} else if (veth_gro_requested(dev)) {
--
2.56.0
next prev parent reply other threads:[~2026-11-15 19:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-15 19:35 [PATCH net-next v3 0/5] veth: link RX queues to their NAPI instances Tianyi Gao
2026-11-15 19:35 ` Tianyi Gao [this message]
2026-11-15 19:35 ` [PATCH net-next v3 2/5] " Tianyi Gao
2026-11-15 19:35 ` [PATCH net-next v3 3/5] selftests: net: veth: test RX queue NAPI links Tianyi Gao
2026-11-15 19:35 ` [PATCH net-next v3 4/5] veth: use persistent NAPI config Tianyi Gao
2026-11-15 19:35 ` [PATCH net-next v3 5/5] selftests: net: veth: test that RX queues keep their NAPI IDs Tianyi Gao
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