From c6d14c84566d6b70ad9dc1618db0dec87cca9300 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 4 Nov 2009 05:43:23 -0800 Subject: [PATCH] net: Introduce for_each_netdev_rcu() iterator Adds RCU management to the list of netdevices. Convert some for_each_netdev() users to RCU version, if it can avoid read_lock-ing dev_base_lock Ie: read_lock(&dev_base_loack); for_each_netdev(net, dev) some_action(); read_unlock(&dev_base_lock); becomes : rcu_read_lock(); for_each_netdev_rcu(net, dev) some_action(); rcu_read_unlock(); Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 30 ++++++++++++++++-------------- net/decnet/af_decnet.c | 6 +++--- net/decnet/dn_fib.c | 6 +++--- net/decnet/dn_route.c | 6 +++--- net/ipv4/devinet.c | 30 +++++++++++------------------- net/ipv6/addrconf.c | 20 +++++++------------- net/ipv6/anycast.c | 6 +++--- net/netrom/nr_route.c | 15 ++++++++------- net/rose/rose_route.c | 18 +++++++++--------- net/sctp/protocol.c | 6 +++--- 11 files changed, 68 insertions(+), 77 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index bcf1083857f..5077de02831 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1081,6 +1081,8 @@ extern rwlock_t dev_base_lock; /* Device list lock */ #define for_each_netdev(net, d) \ list_for_each_entry(d, &(net)->dev_base_head, dev_list) +#define for_each_netdev_rcu(net, d) \ + list_for_each_entry_rcu(d, &(net)->dev_base_head, dev_list) #define for_each_netdev_safe(net, d, n) \ list_for_each_entry_safe(d, n, &(net)->dev_base_head, dev_list) #define for_each_netdev_continue(net, d) \ diff --git a/net/core/dev.c b/net/core/dev.c index 76a1502efe6..bf629ac08b8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -175,7 +175,7 @@ static struct list_head ptype_all __read_mostly; /* Taps */ * The @dev_base_head list is protected by @dev_base_lock and the rtnl * semaphore. * - * Pure readers hold dev_base_lock for reading. + * Pure readers hold dev_base_lock for reading, or rcu_read_lock() * * Writers must hold the rtnl semaphore while they loop through the * dev_base_head list, and hold dev_base_lock for writing when they do the @@ -212,7 +212,7 @@ static int list_netdevice(struct net_device *dev) ASSERT_RTNL(); write_lock_bh(&dev_base_lock); - list_add_tail(&dev->dev_list, &net->dev_base_head); + list_add_tail_rcu(&dev->dev_list, &net->dev_base_head); hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name)); hlist_add_head_rcu(&dev->index_hlist, dev_index_hash(net, dev->ifindex)); @@ -229,7 +229,7 @@ static void unlist_netdevice(struct net_device *dev) /* Unlink dev from the device chain */ write_lock_bh(&dev_base_lock); - list_del(&dev->dev_list); + list_del_rcu(&dev->dev_list); hlist_del_rcu(&dev->name_hlist); hlist_del_rcu(&dev->index_hlist); write_unlock_bh(&dev_base_lock); @@ -799,15 +799,15 @@ struct net_device *dev_get_by_flags(struct net *net, unsigned short if_flags, struct net_device *dev, *ret; ret = NULL; - read_lock(&dev_base_lock); - for_each_netdev(net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(net, dev) { if (((dev->flags ^ if_flags) & mask) == 0) { dev_hold(dev); ret = dev; break; } } - read_unlock(&dev_base_lock); + rcu_read_unlock(); return ret; } EXPORT_SYMBOL(dev_get_by_flags); @@ -3077,18 +3077,18 @@ static int dev_ifconf(struct net *net, char __user *arg) * in detail. */ void *dev_seq_start(struct seq_file *seq, loff_t *pos) - __acquires(dev_base_lock) + __acquires(RCU) { struct net *net = seq_file_net(seq); loff_t off; struct net_device *dev; - read_lock(&dev_base_lock); + rcu_read_lock(); if (!*pos) return SEQ_START_TOKEN; off = 1; - for_each_netdev(net, dev) + for_each_netdev_rcu(net, dev) if (off++ == *pos) return dev; @@ -3097,16 +3097,18 @@ void *dev_seq_start(struct seq_file *seq, loff_t *pos) void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos) { - struct net *net = seq_file_net(seq); + struct net_device *dev = (v == SEQ_START_TOKEN) ? + first_net_device(seq_file_net(seq)) : + next_net_device((struct net_device *)v); + ++*pos; - return v == SEQ_START_TOKEN ? - first_net_device(net) : next_net_device((struct net_device *)v); + return rcu_dereference(dev); } void dev_seq_stop(struct seq_file *seq, void *v) - __releases(dev_base_lock) + __releases(RCU) { - read_unlock(&dev_base_lock); + rcu_read_unlock(); } static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev) diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c index 664965c87e1..2e355841ca9 100644 --- a/net/decnet/af_decnet.c +++ b/net/decnet/af_decnet.c @@ -749,9 +749,9 @@ static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) if (!(saddr->sdn_flags & SDF_WILD)) { if (le16_to_cpu(saddr->sdn_nodeaddrl)) { - read_lock(&dev_base_lock); + rcu_read_lock(); ldev = NULL; - for_each_netdev(&init_net, dev) { + for_each_netdev_rcu(&init_net, dev) { if (!dev->dn_ptr) continue; if (dn_dev_islocal(dev, dn_saddr2dn(saddr))) { @@ -759,7 +759,7 @@ static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) break; } } - read_unlock(&dev_base_lock); + rcu_read_unlock(); if (ldev == NULL) return -EADDRNOTAVAIL; } diff --git a/net/decnet/dn_fib.c b/net/decnet/dn_fib.c index 27ea2e9b080..fd641f65e09 100644 --- a/net/decnet/dn_fib.c +++ b/net/decnet/dn_fib.c @@ -607,8 +607,8 @@ static void dn_fib_del_ifaddr(struct dn_ifaddr *ifa) ASSERT_RTNL(); /* Scan device list */ - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { dn_db = dev->dn_ptr; if (dn_db == NULL) continue; @@ -619,7 +619,7 @@ static void dn_fib_del_ifaddr(struct dn_ifaddr *ifa) } } } - read_unlock(&dev_base_lock); + rcu_read_unlock(); if (found_it == 0) { fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 16, ifa); diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c index 57662cabaf9..860286a3921 100644 --- a/net/decnet/dn_route.c +++ b/net/decnet/dn_route.c @@ -908,8 +908,8 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *old dev_put(dev_out); goto out; } - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { if (!dev->dn_ptr) continue; if (!dn_dev_islocal(dev, oldflp->fld_src)) @@ -922,7 +922,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *old dev_out = dev; break; } - read_unlock(&dev_base_lock); + rcu_read_unlock(); if (dev_out == NULL) goto out; dev_hold(dev_out); diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index ccccaae50b2..8aa7a134c1f 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -876,19 +876,16 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope) if (!addr) addr = ifa->ifa_local; } endfor_ifa(in_dev); -no_in_dev: - rcu_read_unlock(); +no_in_dev: if (addr) - goto out; + goto out_unlock; /* Not loopback addresses on loopback should be preferred in this case. It is importnat that lo is the first interface in dev_base list. */ - read_lock(&dev_base_lock); - rcu_read_lock(); - for_each_netdev(net, dev) { + for_each_netdev_rcu(net, dev) { if ((in_dev = __in_dev_get_rcu(dev)) == NULL) continue; @@ -896,12 +893,11 @@ no_in_dev: if (ifa->ifa_scope != RT_SCOPE_LINK && ifa->ifa_scope <= scope) { addr = ifa->ifa_local; - goto out_unlock_both; + goto out_unlock; } } endfor_ifa(in_dev); } -out_unlock_both: - read_unlock(&dev_base_lock); +out_unlock: rcu_read_unlock(); out: return addr; @@ -962,9 +958,8 @@ __be32 inet_confirm_addr(struct in_device *in_dev, return confirm_addr_indev(in_dev, dst, local, scope); net = dev_net(in_dev->dev); - read_lock(&dev_base_lock); rcu_read_lock(); - for_each_netdev(net, dev) { + for_each_netdev_rcu(net, dev) { if ((in_dev = __in_dev_get_rcu(dev))) { addr = confirm_addr_indev(in_dev, dst, local, scope); if (addr) @@ -972,7 +967,6 @@ __be32 inet_confirm_addr(struct in_device *in_dev, } } rcu_read_unlock(); - read_unlock(&dev_base_lock); return addr; } @@ -1240,18 +1234,18 @@ static void devinet_copy_dflt_conf(struct net *net, int i) { struct net_device *dev; - read_lock(&dev_base_lock); - for_each_netdev(net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(net, dev) { struct in_device *in_dev; - rcu_read_lock(); + in_dev = __in_dev_get_rcu(dev); if (in_dev && !test_bit(i, in_dev->cnf.state)) in_dev->cnf.data[i] = net->ipv4.devconf_dflt->data[i]; - rcu_read_unlock(); } - read_unlock(&dev_base_lock); + rcu_read_unlock(); } +/* called with RTNL locked */ static void inet_forward_change(struct net *net) { struct net_device *dev; @@ -1260,7 +1254,6 @@ static void inet_forward_change(struct net *net) IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on; IPV4_DEVCONF_DFLT(net, FORWARDING) = on; - read_lock(&dev_base_lock); for_each_netdev(net, dev) { struct in_device *in_dev; if (on) @@ -1271,7 +1264,6 @@ static void inet_forward_change(struct net *net) IN_DEV_CONF_SET(in_dev, FORWARDING, on); rcu_read_unlock(); } - read_unlock(&dev_base_lock); } static int devinet_conf_proc(ctl_table *ctl, int write, diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 91864840961..024bba30de2 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -481,9 +481,8 @@ static void addrconf_forward_change(struct net *net, __s32 newf) struct net_device *dev; struct inet6_dev *idev; - read_lock(&dev_base_lock); - for_each_netdev(net, dev) { - rcu_read_lock(); + rcu_read_lock(); + for_each_netdev_rcu(net, dev) { idev = __in6_dev_get(dev); if (idev) { int changed = (!idev->cnf.forwarding) ^ (!newf); @@ -491,9 +490,8 @@ static void addrconf_forward_change(struct net *net, __s32 newf) if (changed) dev_forward_change(idev); } - rcu_read_unlock(); } - read_unlock(&dev_base_lock); + rcu_read_unlock(); } static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old) @@ -1137,10 +1135,9 @@ int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev, hiscore->rule = -1; hiscore->ifa = NULL; - read_lock(&dev_base_lock); rcu_read_lock(); - for_each_netdev(net, dev) { + for_each_netdev_rcu(net, dev) { struct inet6_dev *idev; /* Candidate Source Address (section 4) @@ -1235,7 +1232,6 @@ try_nextdev: read_unlock_bh(&idev->lock); } rcu_read_unlock(); - read_unlock(&dev_base_lock); if (!hiscore->ifa) return -EADDRNOTAVAIL; @@ -4052,9 +4048,8 @@ static void addrconf_disable_change(struct net *net, __s32 newf) struct net_device *dev; struct inet6_dev *idev; - read_lock(&dev_base_lock); - for_each_netdev(net, dev) { - rcu_read_lock(); + rcu_read_lock(); + for_each_netdev_rcu(net, dev) { idev = __in6_dev_get(dev); if (idev) { int changed = (!idev->cnf.disable_ipv6) ^ (!newf); @@ -4062,9 +4057,8 @@ static void addrconf_disable_change(struct net *net, __s32 newf) if (changed) dev_disable_change(idev); } - rcu_read_unlock(); } - read_unlock(&dev_base_lock); + rcu_read_unlock(); } static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old) diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c index 1ae58bec1de..2f00ca83f04 100644 --- a/net/ipv6/anycast.c +++ b/net/ipv6/anycast.c @@ -404,13 +404,13 @@ int ipv6_chk_acast_addr(struct net *net, struct net_device *dev, if (dev) return ipv6_chk_acast_dev(dev, addr); - read_lock(&dev_base_lock); - for_each_netdev(net, dev) + rcu_read_lock(); + for_each_netdev_rcu(net, dev) if (ipv6_chk_acast_dev(dev, addr)) { found = 1; break; } - read_unlock(&dev_base_lock); + rcu_read_unlock(); return found; } diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c index 4eb1ac9a767..aacba76070f 100644 --- a/net/netrom/nr_route.c +++ b/net/netrom/nr_route.c @@ -597,15 +597,15 @@ struct net_device *nr_dev_first(void) { struct net_device *dev, *first = NULL; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM) if (first == NULL || strncmp(dev->name, first->name, 3) < 0) first = dev; } if (first) dev_hold(first); - read_unlock(&dev_base_lock); + rcu_read_unlock(); return first; } @@ -617,16 +617,17 @@ struct net_device *nr_dev_get(ax25_address *addr) { struct net_device *dev; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { - if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM && ax25cmp(addr, (ax25_address *)dev->dev_addr) == 0) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { + if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM && + ax25cmp(addr, (ax25_address *)dev->dev_addr) == 0) { dev_hold(dev); goto out; } } dev = NULL; out: - read_unlock(&dev_base_lock); + rcu_read_unlock(); return dev; } diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index 9478d9b3d97..d936226916f 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -600,13 +600,13 @@ struct net_device *rose_dev_first(void) { struct net_device *dev, *first = NULL; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { if ((dev->flags & IFF_UP) && dev->type == ARPHRD_ROSE) if (first == NULL || strncmp(dev->name, first->name, 3) < 0) first = dev; } - read_unlock(&dev_base_lock); + rcu_read_unlock(); return first; } @@ -618,8 +618,8 @@ struct net_device *rose_dev_get(rose_address *addr) { struct net_device *dev; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { if ((dev->flags & IFF_UP) && dev->type == ARPHRD_ROSE && rosecmp(addr, (rose_address *)dev->dev_addr) == 0) { dev_hold(dev); goto out; @@ -627,7 +627,7 @@ struct net_device *rose_dev_get(rose_address *addr) } dev = NULL; out: - read_unlock(&dev_base_lock); + rcu_read_unlock(); return dev; } @@ -635,14 +635,14 @@ static int rose_dev_exists(rose_address *addr) { struct net_device *dev; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { if ((dev->flags & IFF_UP) && dev->type == ARPHRD_ROSE && rosecmp(addr, (rose_address *)dev->dev_addr) == 0) goto out; } dev = NULL; out: - read_unlock(&dev_base_lock); + rcu_read_unlock(); return dev != NULL; } diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index d9f4cc2c786..fe44c57101d 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -205,14 +205,14 @@ static void sctp_get_local_addr_list(void) struct list_head *pos; struct sctp_af *af; - read_lock(&dev_base_lock); - for_each_netdev(&init_net, dev) { + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) { __list_for_each(pos, &sctp_address_families) { af = list_entry(pos, struct sctp_af, list); af->copy_addrlist(&sctp_local_addr_list, dev); } } - read_unlock(&dev_base_lock); + rcu_read_unlock(); } /* Free the existing local addresses. */ -- 2.20.1