From: Dan Duval <dan.duval@oracle.com>
Date: Wed, 9 Dec 2015 22:13:36 +0000 (-0500)
Subject: Revert "netlink: Replace rhash_portid with bound"
X-Git-Tag: v4.1.12-92~218^2~1
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=14ad67a77a41a2ebd64f4260dd707fbe6109e193;p=users%2Fjedix%2Flinux-maple.git

Revert "netlink: Replace rhash_portid with bound"

Orabug: 22284865

This reverts commit d48623677191e0f035d7afd344f92cf880b01f8e.

That commit, along with 4e27762, have been shown to provoke a hang
in the Oracle Real Application Clusters (RAC) silent-installation
procedure.

Signed-off-by: Dan Duval <dan.duval@oracle.com>
---

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index d139c43ac6e5..eb54d50ecd51 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1017,7 +1017,7 @@ static inline int netlink_compare(struct rhashtable_compare_arg *arg,
 	const struct netlink_compare_arg *x = arg->key;
 	const struct netlink_sock *nlk = ptr;
 
-	return nlk->portid != x->portid ||
+	return nlk->rhash_portid != x->portid ||
 	       !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
 }
 
@@ -1043,7 +1043,7 @@ static int __netlink_insert(struct netlink_table *table, struct sock *sk)
 {
 	struct netlink_compare_arg arg;
 
-	netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
+	netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->rhash_portid);
 	return rhashtable_lookup_insert_key(&table->hash, &arg,
 					    &nlk_sk(sk)->node,
 					    netlink_rhashtable_params);
@@ -1096,8 +1096,8 @@ static int netlink_insert(struct sock *sk, u32 portid)
 
 	lock_sock(sk);
 
-	err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
-	if (nlk_sk(sk)->bound)
+	err = -EBUSY;
+	if (nlk_sk(sk)->portid)
 		goto err;
 
 	err = -ENOMEM;
@@ -1105,7 +1105,7 @@ static int netlink_insert(struct sock *sk, u32 portid)
 	    unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
 		goto err;
 
-	nlk_sk(sk)->portid = portid;
+	nlk_sk(sk)->rhash_portid = portid;
 	sock_hold(sk);
 
 	err = __netlink_insert(table, sk);
@@ -1120,9 +1120,7 @@ static int netlink_insert(struct sock *sk, u32 portid)
 		sock_put(sk);
 	}
 
-	/* We need to ensure that the socket is hashed and visible. */
-	smp_wmb();
-	nlk_sk(sk)->bound = portid;
+	nlk_sk(sk)->portid = portid;
 
 err:
 	release_sock(sk);
@@ -1503,7 +1501,6 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
 	int err;
 	long unsigned int groups = nladdr->nl_groups;
-	bool bound;
 
 	if (addr_len < sizeof(struct sockaddr_nl))
 		return -EINVAL;
@@ -1520,14 +1517,9 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 			return err;
 	}
 
-	bound = nlk->bound;
-	if (bound) {
-		/* Ensure nlk->portid is up-to-date. */
-		smp_rmb();
-
+	if (nlk->portid)
 		if (nladdr->nl_pid != nlk->portid)
 			return -EINVAL;
-	}
 
 	if (nlk->netlink_bind && groups) {
 		int group;
@@ -1543,10 +1535,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 		}
 	}
 
-	/* No need for barriers here as we return to user-space without
-	 * using any of the bound attributes.
-	 */
-	if (!bound) {
+	if (!nlk->portid) {
 		err = nladdr->nl_pid ?
 			netlink_insert(sk, nladdr->nl_pid) :
 			netlink_autobind(sock);
@@ -1594,10 +1583,7 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
 	    !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
 		return -EPERM;
 
-	/* No need for barriers here as we return to user-space without
-	 * using any of the bound attributes.
-	 */
-	if (!nlk->bound)
+	if (!nlk->portid)
 		err = netlink_autobind(sock);
 
 	if (err == 0) {
@@ -2354,13 +2340,10 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 		dst_group = nlk->dst_group;
 	}
 
-	if (!nlk->bound) {
+	if (!nlk->portid) {
 		err = netlink_autobind(sock);
 		if (err)
 			goto out;
-	} else {
-		/* Ensure nlk is hashed and visible. */
-		smp_rmb();
 	}
 
 	/* It's a really convoluted way for userland to ask for mmaped
@@ -3195,7 +3178,7 @@ static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
 	const struct netlink_sock *nlk = data;
 	struct netlink_compare_arg arg;
 
-	netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
+	netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->rhash_portid);
 	return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
 }
 
diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index 14437d9b1965..80b2b7526dfd 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -25,6 +25,7 @@ struct netlink_ring {
 struct netlink_sock {
 	/* struct sock has to be the first member of netlink_sock */
 	struct sock		sk;
+	u32			rhash_portid;
 	u32			portid;
 	u32			dst_portid;
 	u32			dst_group;
@@ -35,7 +36,6 @@ struct netlink_sock {
 	unsigned long		state;
 	size_t			max_recvmsg_len;
 	wait_queue_head_t	wait;
-	bool			bound;
 	bool			cb_running;
 	struct netlink_callback	cb;
 	struct mutex		*cb_mutex;