[PATCH] net: Use nlmsg_unicast() instead of netlink_unicast()

[PATCH] net: Use nlmsg_unicast() instead of netlink_unicast()

[Yajun Deng]

There has 'if (err >0 )' in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 net/ipv4/fib_frontend.c    | 2 +-
 net/ipv4/inet_diag.c       | 5 +----
 net/ipv4/raw_diag.c        | 7 ++-----
 net/ipv4/udp_diag.c        | 6 ++----
 net/mptcp/mptcp_diag.c     | 6 ++----
 net/netfilter/nft_compat.c | 6 ++----
 net/netlink/af_netlink.c   | 2 +-
 net/sctp/diag.c            | 6 ++----
 net/unix/diag.c            | 6 ++----
 9 files changed, 15 insertions(+), 31 deletions(-)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index a933bd6345b1..9fe13e4f5d08 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1376,7 +1376,7 @@ static void nl_fib_input(struct sk_buff *skb)
 	portid = NETLINK_CB(skb).portid;      /* netlink portid */
 	NETLINK_CB(skb).portid = 0;        /* from kernel */
 	NETLINK_CB(skb).dst_group = 0;  /* unicast */
-	netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
+	nlmsg_unicast(net->ipv4.fibnl, skb, portid);
 }
 
 static int __net_init nl_fib_lookup_init(struct net *net)
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index e65f4ef024a4..ef7897226f08 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -580,10 +580,7 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,
 		nlmsg_free(rep);
 		goto out;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
 
 out:
 	if (sk)
diff --git a/net/ipv4/raw_diag.c b/net/ipv4/raw_diag.c
index 1b5b8af27aaf..ccacbde30a2c 100644
--- a/net/ipv4/raw_diag.c
+++ b/net/ipv4/raw_diag.c
@@ -119,11 +119,8 @@ static int raw_diag_dump_one(struct netlink_callback *cb,
 		return err;
 	}
 
-	err = netlink_unicast(net->diag_nlsk, rep,
-			      NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 	return err;
 }
 
diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
index b2cee9a307d4..1ed8c4d78e5c 100644
--- a/net/ipv4/udp_diag.c
+++ b/net/ipv4/udp_diag.c
@@ -77,10 +77,8 @@ static int udp_dump_one(struct udp_table *tbl,
 		kfree_skb(rep);
 		goto out;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 out:
 	if (sk)
 		sock_put(sk);
diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c
index 8f88ddeab6a2..f48eb6315bbb 100644
--- a/net/mptcp/mptcp_diag.c
+++ b/net/mptcp/mptcp_diag.c
@@ -57,10 +57,8 @@ static int mptcp_diag_dump_one(struct netlink_callback *cb,
 		kfree_skb(rep);
 		goto out;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 out:
 	sock_put(sk);
 
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 639c337c885b..aa3397eec330 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -683,10 +683,8 @@ static int nfnl_compat_get_rcu(struct sk_buff *skb,
 		goto out_put;
 	}
 
-	ret = netlink_unicast(info->sk, skb2, NETLINK_CB(skb).portid,
-			      MSG_DONTWAIT);
-	if (ret > 0)
-		ret = 0;
+	ret = nlmsg_unicast(info->sk, skb2, NETLINK_CB(skb).portid);
+
 out_put:
 	rcu_read_lock();
 	module_put(THIS_MODULE);
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index d233ac4a91b6..380f95aacdec 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2471,7 +2471,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 
 	nlmsg_end(skb, rep);
 
-	netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
+	nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid);
 }
 EXPORT_SYMBOL(netlink_ack);
 
diff --git a/net/sctp/diag.c b/net/sctp/diag.c
index 493fc01e5d2b..760b367644c1 100644
--- a/net/sctp/diag.c
+++ b/net/sctp/diag.c
@@ -284,10 +284,8 @@ static int sctp_tsp_dump_one(struct sctp_transport *tsp, void *p)
 		goto out;
 	}
 
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 out:
 	return err;
 }
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 9ff64f9df1f3..7e7d7f45685a 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -295,10 +295,8 @@ static int unix_diag_get_exact(struct sk_buff *in_skb,
 
 		goto again;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 out:
 	if (sk)
 		sock_put(sk);
-- 
2.32.0

Re: [PATCH] net: Use nlmsg_unicast() instead of netlink_unicast()

[Pablo Neira Ayuso]

On Mon, Jul 12, 2021 at 08:53:01PM +0800, Yajun Deng wrote:
> diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
> index 639c337c885b..aa3397eec330 100644
> --- a/net/netfilter/nft_compat.c
> +++ b/net/netfilter/nft_compat.c
> @@ -683,10 +683,8 @@ static int nfnl_compat_get_rcu(struct sk_buff *skb,
>  		goto out_put;
>  	}
>  
> -	ret = netlink_unicast(info->sk, skb2, NETLINK_CB(skb).portid,
> -			      MSG_DONTWAIT);
> -	if (ret > 0)
> -		ret = 0;
> +	ret = nlmsg_unicast(info->sk, skb2, NETLINK_CB(skb).portid);

netfilter needs nfnetlink_unicast to deal with EAGAIN, see e0241ae6ac59

So either:

a) use nfnetlink_unicast.
b) remove this chunk and I'll route a patch to fix this in the
   netfilter tree.

Pick one at your choice.

Thanks.

>  out_put:
>  	rcu_read_lock();
>  	module_put(THIS_MODULE);