From af65bdfce98d7965fbe93a48b8128444a2eea024 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Fri, 20 Apr 2007 14:14:21 -0700 Subject: [NETLINK]: Switch cb_lock spinlock to mutex and allow to override it Switch cb_lock to mutex and allow netlink kernel users to override it with a subsystem specific mutex for consistent locking in dump callbacks. All netlink_dump_start users have been audited not to rely on any side-effects of the previously used spinlock. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) (limited to 'net/netlink/af_netlink.c') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 2cbf1682f63..ec16c9b7b3b 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include @@ -76,7 +77,8 @@ struct netlink_sock { unsigned long state; wait_queue_head_t wait; struct netlink_callback *cb; - spinlock_t cb_lock; + struct mutex *cb_mutex; + struct mutex cb_def_mutex; void (*data_ready)(struct sock *sk, int bytes); struct module *module; }; @@ -108,6 +110,7 @@ struct netlink_table { unsigned long *listeners; unsigned int nl_nonroot; unsigned int groups; + struct mutex *cb_mutex; struct module *module; int registered; }; @@ -370,7 +373,8 @@ static struct proto netlink_proto = { .obj_size = sizeof(struct netlink_sock), }; -static int __netlink_create(struct socket *sock, int protocol) +static int __netlink_create(struct socket *sock, struct mutex *cb_mutex, + int protocol) { struct sock *sk; struct netlink_sock *nlk; @@ -384,7 +388,8 @@ static int __netlink_create(struct socket *sock, int protocol) sock_init_data(sock, sk); nlk = nlk_sk(sk); - spin_lock_init(&nlk->cb_lock); + nlk->cb_mutex = cb_mutex ? : &nlk->cb_def_mutex; + mutex_init(nlk->cb_mutex); init_waitqueue_head(&nlk->wait); sk->sk_destruct = netlink_sock_destruct; @@ -395,6 +400,7 @@ static int __netlink_create(struct socket *sock, int protocol) static int netlink_create(struct socket *sock, int protocol) { struct module *module = NULL; + struct mutex *cb_mutex; struct netlink_sock *nlk; int err = 0; @@ -417,9 +423,10 @@ static int netlink_create(struct socket *sock, int protocol) if (nl_table[protocol].registered && try_module_get(nl_table[protocol].module)) module = nl_table[protocol].module; + cb_mutex = nl_table[protocol].cb_mutex; netlink_unlock_table(); - if ((err = __netlink_create(sock, protocol)) < 0) + if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0) goto out_module; nlk = nlk_sk(sock->sk); @@ -444,14 +451,14 @@ static int netlink_release(struct socket *sock) sock_orphan(sk); nlk = nlk_sk(sk); - spin_lock(&nlk->cb_lock); + mutex_lock(nlk->cb_mutex); if (nlk->cb) { if (nlk->cb->done) nlk->cb->done(nlk->cb); netlink_destroy_callback(nlk->cb); nlk->cb = NULL; } - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); /* OK. Socket is unlinked, and, therefore, no new packets will arrive */ @@ -1266,7 +1273,7 @@ static void netlink_data_ready(struct sock *sk, int len) struct sock * netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), - struct module *module) + struct mutex *cb_mutex, struct module *module) { struct socket *sock; struct sock *sk; @@ -1281,7 +1288,7 @@ netlink_kernel_create(int unit, unsigned int groups, if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) return NULL; - if (__netlink_create(sock, unit) < 0) + if (__netlink_create(sock, cb_mutex, unit) < 0) goto out_sock_release; if (groups < 32) @@ -1305,6 +1312,7 @@ netlink_kernel_create(int unit, unsigned int groups, netlink_table_grab(); nl_table[unit].groups = groups; nl_table[unit].listeners = listeners; + nl_table[unit].cb_mutex = cb_mutex; nl_table[unit].module = module; nl_table[unit].registered = 1; netlink_table_ungrab(); @@ -1347,7 +1355,7 @@ static int netlink_dump(struct sock *sk) if (!skb) goto errout; - spin_lock(&nlk->cb_lock); + mutex_lock(nlk->cb_mutex); cb = nlk->cb; if (cb == NULL) { @@ -1358,7 +1366,7 @@ static int netlink_dump(struct sock *sk) len = cb->dump(skb, cb); if (len > 0) { - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, len); return 0; @@ -1376,13 +1384,13 @@ static int netlink_dump(struct sock *sk) if (cb->done) cb->done(cb); nlk->cb = NULL; - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); netlink_destroy_callback(cb); return 0; errout_skb: - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); kfree_skb(skb); errout: return err; @@ -1414,15 +1422,15 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, } nlk = nlk_sk(sk); /* A dump or destruction is in progress... */ - spin_lock(&nlk->cb_lock); + mutex_lock(nlk->cb_mutex); if (nlk->cb || sock_flag(sk, SOCK_DEAD)) { - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); netlink_destroy_callback(cb); sock_put(sk); return -EBUSY; } nlk->cb = cb; - spin_unlock(&nlk->cb_lock); + mutex_unlock(nlk->cb_mutex); netlink_dump(sk); sock_put(sk); -- cgit v1.2.3