| Message ID | 20240506121156.3180991-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] phonet: no longer hold RTNL in route_dumpit() | expand |
Le maanantaina 6. toukokuuta 2024, 15.11.56 EEST Eric Dumazet a écrit : > route_dumpit() already relies on RCU, RTNL is not needed. > > Also change return value at the end of a dump. > This allows NLMSG_DONE to be appended to the current > skb at the end of a dump, saving a couple of recvmsg() > system calls. > > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Remi Denis-Courmont <courmisch@gmail.com> No objections from me, but TBH I am not familiar with the underlying RTNL locking so my ack wouldn't be worth anything. > --- > net/phonet/pn_netlink.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c > index > 59aebe29689077bfa77d37516aea4617fe3b8a50..c11764ff72d6ac86e643123e2c49de6f0 > 758bf97 100644 --- a/net/phonet/pn_netlink.c > +++ b/net/phonet/pn_netlink.c > @@ -178,7 +178,7 @@ static int fill_route(struct sk_buff *skb, struct > net_device *dev, u8 dst, rtm->rtm_type = RTN_UNICAST; > rtm->rtm_flags = 0; > if (nla_put_u8(skb, RTA_DST, dst) || > - nla_put_u32(skb, RTA_OIF, dev->ifindex)) > + nla_put_u32(skb, RTA_OIF, READ_ONCE(dev->ifindex))) > goto nla_put_failure; > nlmsg_end(skb, nlh); > return 0; > @@ -263,6 +263,7 @@ static int route_doit(struct sk_buff *skb, struct > nlmsghdr *nlh, static int route_dumpit(struct sk_buff *skb, struct > netlink_callback *cb) { > struct net *net = sock_net(skb->sk); > + int err = 0; > u8 addr; > > rcu_read_lock(); > @@ -272,16 +273,16 @@ static int route_dumpit(struct sk_buff *skb, struct > netlink_callback *cb) if (!dev) > continue; > > - if (fill_route(skb, dev, addr << 2, NETLINK_CB(cb- >skb).portid, > - cb->nlh->nlmsg_seq, RTM_NEWROUTE) < 0) > - goto out; > + err = fill_route(skb, dev, addr << 2, > + NETLINK_CB(cb->skb).portid, > + cb->nlh->nlmsg_seq, RTM_NEWROUTE); > + if (err < 0) > + break;; > } > - > -out: > rcu_read_unlock(); > cb->args[0] = addr; > > - return skb->len; > + return err; > } > > int __init phonet_netlink_register(void) > @@ -301,6 +302,6 @@ int __init phonet_netlink_register(void) > rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_DELROUTE, > route_doit, NULL, 0); > rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_GETROUTE, > - NULL, route_dumpit, 0); > + NULL, route_dumpit, RTNL_FLAG_DUMP_UNLOCKED); > return 0; > }
On Mon, 6 May 2024 12:11:56 +0000 Eric Dumazet wrote: > + if (err < 0) > + break;; coccicheck says: net/phonet/pn_netlink.c:280:9-10: Unneeded semicolon
On Mon, May 6, 2024 at 8:26 PM Jakub Kicinski <kuba@kernel.org> wrote: > > On Mon, 6 May 2024 12:11:56 +0000 Eric Dumazet wrote: > > + if (err < 0) > > + break;; > > coccicheck says: > > net/phonet/pn_netlink.c:280:9-10: Unneeded semicolon Nice, thanks ! I will send a V2.
diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c index 59aebe29689077bfa77d37516aea4617fe3b8a50..c11764ff72d6ac86e643123e2c49de6f0758bf97 100644 --- a/net/phonet/pn_netlink.c +++ b/net/phonet/pn_netlink.c @@ -178,7 +178,7 @@ static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst, rtm->rtm_type = RTN_UNICAST; rtm->rtm_flags = 0; if (nla_put_u8(skb, RTA_DST, dst) || - nla_put_u32(skb, RTA_OIF, dev->ifindex)) + nla_put_u32(skb, RTA_OIF, READ_ONCE(dev->ifindex))) goto nla_put_failure; nlmsg_end(skb, nlh); return 0; @@ -263,6 +263,7 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb) { struct net *net = sock_net(skb->sk); + int err = 0; u8 addr; rcu_read_lock(); @@ -272,16 +273,16 @@ static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb) if (!dev) continue; - if (fill_route(skb, dev, addr << 2, NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, RTM_NEWROUTE) < 0) - goto out; + err = fill_route(skb, dev, addr << 2, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, RTM_NEWROUTE); + if (err < 0) + break;; } - -out: rcu_read_unlock(); cb->args[0] = addr; - return skb->len; + return err; } int __init phonet_netlink_register(void) @@ -301,6 +302,6 @@ int __init phonet_netlink_register(void) rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_DELROUTE, route_doit, NULL, 0); rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_GETROUTE, - NULL, route_dumpit, 0); + NULL, route_dumpit, RTNL_FLAG_DUMP_UNLOCKED); return 0; }
route_dumpit() already relies on RCU, RTNL is not needed. Also change return value at the end of a dump. This allows NLMSG_DONE to be appended to the current skb at the end of a dump, saving a couple of recvmsg() system calls. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Remi Denis-Courmont <courmisch@gmail.com> --- net/phonet/pn_netlink.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)