[PATCH net-next v1 4/4] net: drop rtnl_lock for queue_mgmt operations

Stanislav Fomichev
2025-03-07T15:57:32Z

All drivers that use queue API are already converted to use
netdev instance lock. Move netdev instance lock management to
the netlink layer and drop rtnl_lock.

Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 4 ++--
drivers/net/netdevsim/netdev.c | 4 ++--
net/core/devmem.c | 3 ++-
net/core/netdev-genl.c | 18 +++++-------------
net/core/netdev_rx_queue.c | 15 +++++----------
5 files changed, 16 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 1a1e6da77777..9b936cfc1d29 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11380,14 +11380,14 @@ static void bnxt_irq_affinity_notify(struct irq_affinity_notify *notify,
if (pcie_tph_set_st_entry(irq->bp->pdev, irq->msix_nr, tag))
return;

- rtnl_lock();
+ netdev_lock(irq->bp->dev);
if (netif_running(irq->bp->dev)) {
err = netdev_rx_queue_restart(irq->bp->dev, irq->ring_nr);
if (err)
netdev_err(irq->bp->dev,
"RX queue restart failed: err=%d\n", err);
}
- rtnl_unlock();
+ netdev_unlock(irq->bp->dev);
}

static void bnxt_irq_affinity_release(struct kref *ref)
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 54d03b0628d2..1ba2ff5e4453 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -786,7 +786,7 @@ nsim_qreset_write(struct file *file, const char __user *data,
if (ret != 2)
return -EINVAL;

- rtnl_lock();
+ netdev_lock(ns->netdev);
if (queue >= ns->netdev->real_num_rx_queues) {
ret = -EINVAL;
goto exit_unlock;
@@ -800,7 +800,7 @@ nsim_qreset_write(struct file *file, const char __user *data,

ret = count;
exit_unlock:
- rtnl_unlock();
+ netdev_unlock(ns->netdev);
return ret;
}

diff --git a/net/core/devmem.c b/net/core/devmem.c
index c16cdac46bed..e48eb42d7377 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -132,9 +132,10 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
rxq->mp_params.mp_priv = NULL;
rxq->mp_params.mp_ops = NULL;

+ netdev_lock(binding->dev);
rxq_idx = get_netdev_rx_queue_index(rxq);
-
WARN_ON(netdev_rx_queue_restart(binding->dev, rxq_idx));
+ netdev_unlock(binding->dev);
}

net_devmem_dmabuf_binding_put(binding);
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 8acdeeae24e7..1de28f9e0219 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -481,8 +481,6 @@ int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info)
if (!rsp)
return -ENOMEM;

- rtnl_lock();
-
netdev = netdev_get_by_index_lock(genl_info_net(info), ifindex);
if (netdev) {
err = netdev_nl_queue_fill(rsp, netdev, q_id, q_type, info);
@@ -491,8 +489,6 @@ int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info)
err = -ENODEV;
}

- rtnl_unlock();
-
if (err)
goto err_free_msg;

@@ -541,7 +537,6 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
if (info->attrs[NETDEV_A_QUEUE_IFINDEX])
ifindex = nla_get_u32(info->attrs[NETDEV_A_QUEUE_IFINDEX]);

- rtnl_lock();
if (ifindex) {
netdev = netdev_get_by_index_lock(net, ifindex);
if (netdev) {
@@ -559,7 +554,6 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
ctx->txq_idx = 0;
}
}
- rtnl_unlock();

return err;
}
@@ -860,12 +854,11 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
}

mutex_lock(&priv->lock);
- rtnl_lock();

- netdev = __dev_get_by_index(genl_info_net(info), ifindex);
+ netdev = netdev_get_by_index_lock(genl_info_net(info), ifindex);
if (!netdev || !netif_device_present(netdev)) {
err = -ENODEV;
- goto err_unlock;
+ goto err_unlock_sock;
}

if (dev_xdp_prog_count(netdev)) {
@@ -918,14 +911,15 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
if (err)
goto err_unbind;

- rtnl_unlock();
+ netdev_unlock(netdev);

return 0;

err_unbind:
net_devmem_unbind_dmabuf(binding);
err_unlock:
- rtnl_unlock();
+ netdev_unlock(netdev);
+err_unlock_sock:
mutex_unlock(&priv->lock);
err_genlmsg_free:
nlmsg_free(rsp);
@@ -945,9 +939,7 @@ void netdev_nl_sock_priv_destroy(struct netdev_nl_sock *priv)

mutex_lock(&priv->lock);
list_for_each_entry_safe(binding, temp, &priv->bindings, list) {
- rtnl_lock();
net_devmem_unbind_dmabuf(binding);
- rtnl_unlock();
}
mutex_unlock(&priv->lock);
}
diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
index 7419c41fd3cb..8fd5d784ac09 100644
--- a/net/core/netdev_rx_queue.c
+++ b/net/core/netdev_rx_queue.c
@@ -18,7 +18,7 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
!qops->ndo_queue_mem_alloc || !qops->ndo_queue_start)
return -EOPNOTSUPP;

- ASSERT_RTNL();
+ netdev_assert_locked(dev);

new_mem = kvzalloc(qops->ndo_queue_mem_size, GFP_KERNEL);
if (!new_mem)
@@ -30,8 +30,6 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
goto err_free_new_mem;
}

- netdev_lock(dev);
-
err = qops->ndo_queue_mem_alloc(dev, new_mem, rxq_idx);
if (err)
goto err_free_old_mem;
@@ -54,8 +52,6 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)

qops->ndo_queue_mem_free(dev, old_mem);

- netdev_unlock(dev);
-
kvfree(old_mem);
kvfree(new_mem);

@@ -80,7 +76,6 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
qops->ndo_queue_mem_free(dev, new_mem);

err_free_old_mem:
- netdev_unlock(dev);
kvfree(old_mem);

err_free_new_mem:
@@ -118,9 +113,9 @@ int net_mp_open_rxq(struct net_device *dev, unsigned ifq_idx,
{
int ret;

- rtnl_lock();
+ netdev_lock(dev);
ret = __net_mp_open_rxq(dev, ifq_idx, p);
- rtnl_unlock();
+ netdev_unlock(dev);
return ret;
}

@@ -153,7 +148,7 @@ static void __net_mp_close_rxq(struct net_device *dev, unsigned ifq_idx,
void net_mp_close_rxq(struct net_device *dev, unsigned ifq_idx,
struct pp_memory_provider_params *old_p)
{
- rtnl_lock();
+ netdev_lock(dev);
__net_mp_close_rxq(dev, ifq_idx, old_p);
- rtnl_unlock();
+ netdev_unlock(dev);
}
--
2.48.1