X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=datapath%2Fvport.c;h=8ef96f73e1fc6ea7e77cb1881d5617e0be93ab85;hb=d19cedb28fa32091d149749d326707d8405cbbb6;hp=8289c01aa8c3b0d97241a346bd0bf9dd83e61f2c;hpb=c19e653509deb3f1002c4ed99714e16549ec74e9;p=openvswitch diff --git a/datapath/vport.c b/datapath/vport.c index 8289c01a..8ef96f73 100644 --- a/datapath/vport.c +++ b/datapath/vport.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -38,55 +39,10 @@ static const struct vport_ops *base_vport_ops_list[] = { static const struct vport_ops **vport_ops_list; static int n_vport_types; +/* Protected by RCU read lock for reading, RTNL lock for writing. */ static struct hlist_head *dev_table; #define VPORT_HASH_BUCKETS 1024 -/* Both RTNL lock and vport_mutex need to be held when updating dev_table. - * - * If you use vport_locate and then perform some operations, you need to hold - * one of these locks if you don't want the vport to be deleted out from under - * you. - * - * If you get a reference to a vport through a datapath, it is protected - * by RCU and you need to hold rcu_read_lock instead when reading. - * - * If multiple locks are taken, the hierarchy is: - * 1. RTNL - * 2. DP - * 3. vport - */ -static DEFINE_MUTEX(vport_mutex); - -/** - * vport_lock - acquire vport lock - * - * Acquire global vport lock. See above comment about locking requirements - * and specific function definitions. May sleep. - */ -void vport_lock(void) -{ - mutex_lock(&vport_mutex); -} - -/** - * vport_unlock - release vport lock - * - * Release lock acquired with vport_lock. - */ -void vport_unlock(void) -{ - mutex_unlock(&vport_mutex); -} - -#define ASSERT_VPORT() \ -do { \ - if (unlikely(!mutex_is_locked(&vport_mutex))) { \ - pr_err("vport lock not held at %s (%d)\n", \ - __FILE__, __LINE__); \ - dump_stack(); \ - } \ -} while (0) - /** * vport_init - initialize vport subsystem * @@ -166,9 +122,7 @@ static struct hlist_head *hash_bucket(const char *name) * * @name: name of port to find * - * Either RTNL or vport lock must be acquired before calling this function - * and held while using the found port. See the locking comments at the - * top of the file. + * Must be called with RTNL or RCU read lock. */ struct vport *vport_locate(const char *name) { @@ -176,32 +130,11 @@ struct vport *vport_locate(const char *name) struct vport *vport; struct hlist_node *node; - if (unlikely(!mutex_is_locked(&vport_mutex) && !rtnl_is_locked())) { - pr_err("neither RTNL nor vport lock held in vport_locate\n"); - dump_stack(); - } - - rcu_read_lock(); - - hlist_for_each_entry(vport, node, bucket, hash_node) + hlist_for_each_entry_rcu(vport, node, bucket, hash_node) if (!strcmp(name, vport_get_name(vport))) - goto out; - - vport = NULL; - -out: - rcu_read_unlock(); - return vport; -} + return vport; -static void register_vport(struct vport *vport) -{ - hlist_add_head(&vport->hash_node, hash_bucket(vport_get_name(vport))); -} - -static void unregister_vport(struct vport *vport) -{ - hlist_del(&vport->hash_node); + return NULL; } static void release_vport(struct kobject *kobj) @@ -270,6 +203,9 @@ struct vport *vport_alloc(int priv_size, const struct vport_ops *ops, const stru * @vport: vport to free * * Frees a vport allocated with vport_alloc() when it is no longer needed. + * + * The caller must ensure that an RCU grace period has passed since the last + * time @vport was in a datapath. */ void vport_free(struct vport *vport) { @@ -285,8 +221,7 @@ void vport_free(struct vport *vport) * @parms: Information about new vport. * * Creates a new vport with the specified configuration (which is dependent on - * device type) and attaches it to a datapath. Both RTNL and vport locks must - * be held. + * device type) and attaches it to a datapath. RTNL lock must be held. */ struct vport *vport_add(const struct vport_parms *parms) { @@ -295,7 +230,6 @@ struct vport *vport_add(const struct vport_parms *parms) int i; ASSERT_RTNL(); - ASSERT_VPORT(); for (i = 0; i < n_vport_types; i++) { if (vport_ops_list[i]->type == parms->type) { @@ -305,7 +239,8 @@ struct vport *vport_add(const struct vport_parms *parms) goto out; } - register_vport(vport); + hlist_add_head_rcu(&vport->hash_node, + hash_bucket(vport_get_name(vport))); return vport; } } @@ -335,19 +270,18 @@ int vport_set_options(struct vport *vport, struct nlattr *options) } /** - * vport_del - delete existing vport device (for kernel callers) + * vport_del - delete existing vport device * * @vport: vport to delete. * * Detaches @vport from its datapath and destroys it. It is possible to fail - * for reasons such as lack of memory. Both RTNL and vport locks must be held. + * for reasons such as lack of memory. RTNL lock must be held. */ int vport_del(struct vport *vport) { ASSERT_RTNL(); - ASSERT_VPORT(); - unregister_vport(vport); + hlist_del_rcu(&vport->hash_node); return vport->ops->destroy(vport); } @@ -406,7 +340,7 @@ int vport_set_addr(struct vport *vport, const unsigned char *addr) } /** - * vport_set_stats - sets offset device stats (for kernel callers) + * vport_set_stats - sets offset device stats * * @vport: vport on which to set stats * @stats: stats to set @@ -414,7 +348,9 @@ int vport_set_addr(struct vport *vport, const unsigned char *addr) * Provides a set of transmit, receive, and error stats to be added as an * offset to the collect data when stats are retreived. Some devices may not * support setting the stats, in which case the result will always be - * -EOPNOTSUPP. RTNL lock must be held. + * -EOPNOTSUPP. + * + * Must be called with RTNL lock. */ int vport_set_stats(struct vport *vport, struct rtnl_link_stats64 *stats) { @@ -448,8 +384,7 @@ const char *vport_get_name(const struct vport *vport) * * @vport: vport from which to retrieve the type. * - * Retrieves the type of the given device. Either RTNL lock or rcu_read_lock - * must be held. + * Retrieves the type of the given device. */ enum odp_vport_type vport_get_type(const struct vport *vport) { @@ -498,12 +433,14 @@ static int vport_call_get_stats(struct vport *vport, struct rtnl_link_stats64 *s } /** - * vport_get_stats - retrieve device stats (for kernel callers) + * vport_get_stats - retrieve device stats * * @vport: vport from which to retrieve the stats * @stats: location to store stats * * Retrieves transmit, receive, and error stats for the given device. + * + * Must be called with RTNL lock or rcu_read_lock. */ int vport_get_stats(struct vport *vport, struct rtnl_link_stats64 *stats) { @@ -585,8 +522,9 @@ int vport_get_stats(struct vport *vport, struct rtnl_link_stats64 *stats) * * @vport: vport from which to retrieve the flags * - * Retrieves the flags of the given device. Either RTNL lock or rcu_read_lock - * must be held. + * Retrieves the flags of the given device. + * + * Must be called with RTNL lock or rcu_read_lock. */ unsigned vport_get_flags(const struct vport *vport) { @@ -598,8 +536,9 @@ unsigned vport_get_flags(const struct vport *vport) * * @vport: vport on which to check status. * - * Checks whether the given device is running. Either RTNL lock or - * rcu_read_lock must be held. + * Checks whether the given device is running. + * + * Must be called with RTNL lock or rcu_read_lock. */ int vport_is_running(const struct vport *vport) { @@ -611,8 +550,9 @@ int vport_is_running(const struct vport *vport) * * @vport: vport from which to check status * - * Retrieves the RFC2863 operstate of the given device. Either RTNL lock or - * rcu_read_lock must be held. + * Retrieves the RFC2863 operstate of the given device. + * + * Must be called with RTNL lock or rcu_read_lock. */ unsigned char vport_get_operstate(const struct vport *vport) { @@ -626,8 +566,9 @@ unsigned char vport_get_operstate(const struct vport *vport) * * Retrieves the system interface index of the given device or 0 if * the device does not have one (in the case of virtual ports). - * Returns a negative index on error. Either RTNL lock or - * rcu_read_lock must be held. + * Returns a negative index on error. + * + * Must be called with RTNL lock or rcu_read_lock. */ int vport_get_ifindex(const struct vport *vport) { @@ -645,8 +586,9 @@ int vport_get_ifindex(const struct vport *vport) * Retrieves the system link index of the given device. The link is the index * of the interface on which the packet will actually be sent. In most cases * this is the same as the ifindex but may be different for tunnel devices. - * Returns a negative index on error. Either RTNL lock or rcu_read_lock must - * be held. + * Returns a negative index on error. + * + * Must be called with RTNL lock or rcu_read_lock. */ int vport_get_iflink(const struct vport *vport) { @@ -659,15 +601,18 @@ int vport_get_iflink(const struct vport *vport) } /** - * vport_get_mtu - retrieve device MTU (for kernel callers) + * vport_get_mtu - retrieve device MTU * * @vport: vport from which to retrieve MTU * - * Retrieves the MTU of the given device. Either RTNL lock or rcu_read_lock - * must be held. + * Retrieves the MTU of the given device. Returns 0 if @vport does not have an + * MTU (as e.g. some tunnels do not). Either RTNL lock or rcu_read_lock must + * be held. */ int vport_get_mtu(const struct vport *vport) { + if (!vport->ops->get_mtu) + return 0; return vport->ops->get_mtu(vport); } @@ -679,11 +624,13 @@ int vport_get_mtu(const struct vport *vport) * * Retrieves the configuration of the given device, appending an * %ODP_VPORT_ATTR_OPTIONS attribute that in turn contains nested - * vport-specific attributes to @skb. Either RTNL lock or rcu_read_lock must - * be held. + * vport-specific attributes to @skb. * * Returns 0 if successful, -EMSGSIZE if @skb has insufficient room, or another - * negative error code if a real error occurred. + * negative error code if a real error occurred. If an error occurs, @skb is + * left unmodified. + * + * Must be called with RTNL lock or rcu_read_lock. */ int vport_get_options(const struct vport *vport, struct sk_buff *skb) { @@ -695,8 +642,10 @@ int vport_get_options(const struct vport *vport, struct sk_buff *skb) if (vport->ops->get_options) { int err = vport->ops->get_options(vport, skb); - if (err) + if (err) { + nla_nest_cancel(skb, nla); return err; + } } nla_nest_end(skb, nla); @@ -763,7 +712,7 @@ int vport_send(struct vport *vport, struct sk_buff *skb) int sent; mtu = vport_get_mtu(vport); - if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) { + if (mtu && unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) { if (net_ratelimit()) pr_warn("%s: dropped over-mtu packet: %d > %d\n", dp_name(vport->dp), packet_length(skb), mtu);