diff options
Diffstat (limited to 'net/can')
| -rw-r--r-- | net/can/af_can.c | 67 | ||||
| -rw-r--r-- | net/can/bcm.c | 2 | ||||
| -rw-r--r-- | net/can/raw.c | 2 |
3 files changed, 44 insertions, 27 deletions
diff --git a/net/can/af_can.c b/net/can/af_can.c index 733d66f1b05..094fc5332d4 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -84,8 +84,8 @@ static DEFINE_SPINLOCK(can_rcvlists_lock); static struct kmem_cache *rcv_cache __read_mostly; /* table of registered CAN protocols */ -static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; -static DEFINE_SPINLOCK(proto_tab_lock); +static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; +static DEFINE_MUTEX(proto_tab_lock); struct timer_list can_stattimer; /* timer for statistics update */ struct s_stats can_stats; /* packet statistics */ @@ -115,11 +115,29 @@ static void can_sock_destruct(struct sock *sk) skb_queue_purge(&sk->sk_receive_queue); } +static const struct can_proto *can_get_proto(int protocol) +{ + const struct can_proto *cp; + + rcu_read_lock(); + cp = rcu_dereference(proto_tab[protocol]); + if (cp && !try_module_get(cp->prot->owner)) + cp = NULL; + rcu_read_unlock(); + + return cp; +} + +static inline void can_put_proto(const struct can_proto *cp) +{ + module_put(cp->prot->owner); +} + static int can_create(struct net *net, struct socket *sock, int protocol, int kern) { struct sock *sk; - struct can_proto *cp; + const struct can_proto *cp; int err = 0; sock->state = SS_UNCONNECTED; @@ -130,9 +148,12 @@ static int can_create(struct net *net, struct socket *sock, int protocol, if (!net_eq(net, &init_net)) return -EAFNOSUPPORT; + cp = can_get_proto(protocol); + #ifdef CONFIG_MODULES - /* try to load protocol module kernel is modular */ - if (!proto_tab[protocol]) { + if (!cp) { + /* try to load protocol module if kernel is modular */ + err = request_module("can-proto-%d", protocol); /* @@ -143,22 +164,18 @@ static int can_create(struct net *net, struct socket *sock, int protocol, if (err && printk_ratelimit()) printk(KERN_ERR "can: request_module " "(can-proto-%d) failed.\n", protocol); + + cp = can_get_proto(protocol); } #endif - spin_lock(&proto_tab_lock); - cp = proto_tab[protocol]; - if (cp && !try_module_get(cp->prot->owner)) - cp = NULL; - spin_unlock(&proto_tab_lock); - /* check for available protocol and correct usage */ if (!cp) return -EPROTONOSUPPORT; if (cp->type != sock->type) { - err = -EPROTONOSUPPORT; + err = -EPROTOTYPE; goto errout; } @@ -183,7 +200,7 @@ static int can_create(struct net *net, struct socket *sock, int protocol, } errout: - module_put(cp->prot->owner); + can_put_proto(cp); return err; } @@ -679,7 +696,7 @@ drop: * -EBUSY protocol already in use * -ENOBUF if proto_register() fails */ -int can_proto_register(struct can_proto *cp) +int can_proto_register(const struct can_proto *cp) { int proto = cp->protocol; int err = 0; @@ -694,15 +711,16 @@ int can_proto_register(struct can_proto *cp) if (err < 0) return err; - spin_lock(&proto_tab_lock); + mutex_lock(&proto_tab_lock); + if (proto_tab[proto]) { printk(KERN_ERR "can: protocol %d already registered\n", proto); err = -EBUSY; } else - proto_tab[proto] = cp; + rcu_assign_pointer(proto_tab[proto], cp); - spin_unlock(&proto_tab_lock); + mutex_unlock(&proto_tab_lock); if (err < 0) proto_unregister(cp->prot); @@ -715,17 +733,16 @@ EXPORT_SYMBOL(can_proto_register); * can_proto_unregister - unregister CAN transport protocol * @cp: pointer to CAN protocol structure */ -void can_proto_unregister(struct can_proto *cp) +void can_proto_unregister(const struct can_proto *cp) { int proto = cp->protocol; - spin_lock(&proto_tab_lock); - if (!proto_tab[proto]) { - printk(KERN_ERR "BUG: can: protocol %d is not registered\n", - proto); - } - proto_tab[proto] = NULL; - spin_unlock(&proto_tab_lock); + mutex_lock(&proto_tab_lock); + BUG_ON(proto_tab[proto] != cp); + rcu_assign_pointer(proto_tab[proto], NULL); + mutex_unlock(&proto_tab_lock); + + synchronize_rcu(); proto_unregister(cp->prot); } diff --git a/net/can/bcm.c b/net/can/bcm.c index 8a6a05e7c3c..cced806098a 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -1601,7 +1601,7 @@ static struct proto bcm_proto __read_mostly = { .init = bcm_init, }; -static struct can_proto bcm_can_proto __read_mostly = { +static const struct can_proto bcm_can_proto = { .type = SOCK_DGRAM, .protocol = CAN_BCM, .ops = &bcm_ops, diff --git a/net/can/raw.c b/net/can/raw.c index 0eb39a7fdf6..dea99a6e596 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -774,7 +774,7 @@ static struct proto raw_proto __read_mostly = { .init = raw_init, }; -static struct can_proto raw_can_proto __read_mostly = { +static const struct can_proto raw_can_proto = { .type = SOCK_RAW, .protocol = CAN_RAW, .ops = &raw_ops, |