net: make netdev netlink ops hold netdev_lock()

In prep for dropping rtnl_lock, start locking netdev->lock in netlink
genl ops. We need to be using netdev->up instead of flags & IFF_UP.

We can remove the RCU lock protection for the NAPI since NAPI list
is protected by netdev->lock already.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250115035319.559603-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index cfd88bc6ce5f485f27088d5de28cc96693110ae0..2ef50a3ee4a18f2ce26079ac4ef12d836191bf84 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -768,7 +768,8 @@ static struct napi_struct *napi_by_id(unsigned int napi_id)
 }
 
 /* must be called under rcu_read_lock(), as we dont take a reference */
-struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id)
+static struct napi_struct *
+netdev_napi_by_id(struct net *net, unsigned int napi_id)
 {
        struct napi_struct *napi;
 

diff --git a/net/core/dev.h b/net/core/dev.h
index ef37e2dd44f4417cbb23cd5ad60f2154cb130b04..a5b166bbd169a0aea925dd794db25f26418de87d 100644 (file)
--- a/net/core/dev.h
+++ b/net/core/dev.h
@@ -23,7 +23,6 @@ struct sd_flow_limit {
 
 extern int netdev_flow_limit_table_len;
 
-struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id);
 struct napi_struct *
 netdev_napi_by_id_lock(struct net *net, unsigned int napi_id);
 struct net_device *dev_get_by_napi_id(unsigned int napi_id);

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index c59619a2ec236e5a9a55f86ef2170fd00c896b53..810a446ab62c593ad6a990caff7ff30c4ed8fb24 100644 (file)
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -167,7 +167,7 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi,
        void *hdr;
        pid_t pid;
 
-       if (!(napi->dev->flags & IFF_UP))
+       if (!napi->dev->up)
                return 0;
 
        hdr = genlmsg_iput(rsp, info);
@@ -230,17 +230,16 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
                return -ENOMEM;
 
        rtnl_lock();
-       rcu_read_lock();
 
-       napi = netdev_napi_by_id(genl_info_net(info), napi_id);
+       napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);
        if (napi) {
                err = netdev_nl_napi_fill_one(rsp, napi, info);
+               netdev_unlock(napi->dev);
        } else {
                NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_ID]);
                err = -ENOENT;
        }
 
-       rcu_read_unlock();
        rtnl_unlock();
 
        if (err) {
@@ -266,7 +265,7 @@ netdev_nl_napi_dump_one(struct net_device *netdev, struct sk_buff *rsp,
        unsigned int prev_id;
        int err = 0;
 
-       if (!(netdev->flags & IFF_UP))
+       if (!netdev->up)
                return err;
 
        prev_id = UINT_MAX;
@@ -303,13 +302,15 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
        rtnl_lock();
        if (ifindex) {
-               netdev = __dev_get_by_index(net, ifindex);
-               if (netdev)
+               netdev = netdev_get_by_index_lock(net, ifindex);
+               if (netdev) {
                        err = netdev_nl_napi_dump_one(netdev, skb, info, ctx);
-               else
+                       netdev_unlock(netdev);
+               } else {
                        err = -ENODEV;
+               }
        } else {
-               for_each_netdev_dump(net, netdev, ctx->ifindex) {
+               for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) {
                        err = netdev_nl_napi_dump_one(netdev, skb, info, ctx);
                        if (err < 0)
                                break;
@@ -358,17 +359,16 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
        napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_ID]);
 
        rtnl_lock();
-       rcu_read_lock();
 
-       napi = netdev_napi_by_id(genl_info_net(info), napi_id);
+       napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);
        if (napi) {
                err = netdev_nl_napi_set_config(napi, info);
+               netdev_unlock(napi->dev);
        } else {
                NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_ID]);
                err = -ENOENT;
        }
 
-       rcu_read_unlock();
        rtnl_unlock();
 
        return err;
@@ -442,7 +442,7 @@ netdev_nl_queue_fill(struct sk_buff *rsp, struct net_device *netdev, u32 q_idx,
 {
        int err;
 
-       if (!(netdev->flags & IFF_UP))
+       if (!netdev->up)
                return -ENOENT;
 
        err = netdev_nl_queue_validate(netdev, q_idx, q_type);
@@ -474,11 +474,13 @@ int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info)
 
        rtnl_lock();
 
-       netdev = __dev_get_by_index(genl_info_net(info), ifindex);
-       if (netdev)
+       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);
-       else
+               netdev_unlock(netdev);
+       } else {
                err = -ENODEV;
+       }
 
        rtnl_unlock();
 
@@ -499,7 +501,7 @@ netdev_nl_queue_dump_one(struct net_device *netdev, struct sk_buff *rsp,
 {
        int err = 0;
 
-       if (!(netdev->flags & IFF_UP))
+       if (!netdev->up)
                return err;
 
        for (; ctx->rxq_idx < netdev->real_num_rx_queues; ctx->rxq_idx++) {
@@ -532,13 +534,15 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
        rtnl_lock();
        if (ifindex) {
-               netdev = __dev_get_by_index(net, ifindex);
-               if (netdev)
+               netdev = netdev_get_by_index_lock(net, ifindex);
+               if (netdev) {
                        err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
-               else
+                       netdev_unlock(netdev);
+               } else {
                        err = -ENODEV;
+               }
        } else {
-               for_each_netdev_dump(net, netdev, ctx->ifindex) {
+               for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) {
                        err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
                        if (err < 0)
                                break;