summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2012-08-22 17:19:46 +0000
committerDavid S. Miller <davem@davemloft.net>2012-08-22 21:50:36 -0700
commit0115e8e30d6fcdd4b8faa30d3ffd90859a591f51 (patch)
tree725026e2192e57b98366947ab53c73689ca040a8
parentbf277b0ccea7d2422b85e232017ce3fddbe9c49c (diff)
net: remove delay at device dismantle
I noticed extra one second delay in device dismantle, tracked down to a call to dst_dev_event() while some call_rcu() are still in RCU queues. These call_rcu() were posted by rt_free(struct rtable *rt) calls. We then wait a little (but one second) in netdev_wait_allrefs() before kicking again NETDEV_UNREGISTER. As the call_rcu() are now completed, dst_dev_event() can do the needed device swap on busy dst. To solve this problem, add a new NETDEV_UNREGISTER_FINAL, called after a rcu_barrier(), but outside of RTNL lock. Use NETDEV_UNREGISTER_FINAL with care ! Change dst_dev_event() handler to react to NETDEV_UNREGISTER_FINAL Also remove NETDEV_UNREGISTER_BATCH, as its not used anymore after IP cache removal. With help from Gao feng Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Mahesh Bandewar <maheshb@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netdevice.h2
-rw-r--r--net/core/dev.c22
-rw-r--r--net/core/dst.c2
-rw-r--r--net/core/fib_rules.c3
-rw-r--r--net/core/rtnetlink.c2
-rw-r--r--net/ipv4/devinet.c6
-rw-r--r--net/ipv4/fib_frontend.c8
-rw-r--r--net/ipv6/addrconf.c6
8 files changed, 27 insertions, 24 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4936f09a9333..9ad7fa8c10e0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1553,7 +1553,7 @@ struct packet_type {
#define NETDEV_PRE_TYPE_CHANGE 0x000E
#define NETDEV_POST_TYPE_CHANGE 0x000F
#define NETDEV_POST_INIT 0x0010
-#define NETDEV_UNREGISTER_BATCH 0x0011
+#define NETDEV_UNREGISTER_FINAL 0x0011
#define NETDEV_RELEASE 0x0012
#define NETDEV_NOTIFY_PEERS 0x0013
#define NETDEV_JOIN 0x0014
diff --git a/net/core/dev.c b/net/core/dev.c
index 088923fe4066..0640d2a859c6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1406,7 +1406,6 @@ rollback:
nb->notifier_call(nb, NETDEV_DOWN, dev);
}
nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
- nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
}
}
@@ -1448,7 +1447,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
nb->notifier_call(nb, NETDEV_DOWN, dev);
}
nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
- nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
}
}
unlock:
@@ -1468,7 +1466,8 @@ EXPORT_SYMBOL(unregister_netdevice_notifier);
int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
{
- ASSERT_RTNL();
+ if (val != NETDEV_UNREGISTER_FINAL)
+ ASSERT_RTNL();
return raw_notifier_call_chain(&netdev_chain, val, dev);
}
EXPORT_SYMBOL(call_netdevice_notifiers);
@@ -5331,10 +5330,6 @@ static void rollback_registered_many(struct list_head *head)
netdev_unregister_kobject(dev);
}
- /* Process any work delayed until the end of the batch */
- dev = list_first_entry(head, struct net_device, unreg_list);
- call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
-
synchronize_net();
list_for_each_entry(dev, head, unreg_list)
@@ -5787,9 +5782,8 @@ static void netdev_wait_allrefs(struct net_device *dev)
/* Rebroadcast unregister notification */
call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
- /* don't resend NETDEV_UNREGISTER_BATCH, _BATCH users
- * should have already handle it the first time */
-
+ rcu_barrier();
+ call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev);
if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
&dev->state)) {
/* We must not have linkwatch events
@@ -5851,9 +5845,8 @@ void netdev_run_todo(void)
__rtnl_unlock();
- /* Wait for rcu callbacks to finish before attempting to drain
- * the device list. This usually avoids a 250ms wait.
- */
+
+ /* Wait for rcu callbacks to finish before next phase */
if (!list_empty(&list))
rcu_barrier();
@@ -5862,6 +5855,8 @@ void netdev_run_todo(void)
= list_first_entry(&list, struct net_device, todo_list);
list_del(&dev->todo_list);
+ call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev);
+
if (unlikely(dev->reg_state != NETREG_UNREGISTERING)) {
pr_err("network todo '%s' but state %d\n",
dev->name, dev->reg_state);
@@ -6256,7 +6251,6 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
the device is just moving and can keep their slaves up.
*/
call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
- call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
/*
diff --git a/net/core/dst.c b/net/core/dst.c
index 56d63612e1e4..f6593d238e9a 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -374,7 +374,7 @@ static int dst_dev_event(struct notifier_block *this, unsigned long event,
struct dst_entry *dst, *last = NULL;
switch (event) {
- case NETDEV_UNREGISTER:
+ case NETDEV_UNREGISTER_FINAL:
case NETDEV_DOWN:
mutex_lock(&dst_gc_mutex);
for (dst = dst_busy_list; dst; dst = dst->next) {
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index ab7db83236c9..585093755c23 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -711,15 +711,16 @@ static int fib_rules_event(struct notifier_block *this, unsigned long event,
struct net *net = dev_net(dev);
struct fib_rules_ops *ops;
- ASSERT_RTNL();
switch (event) {
case NETDEV_REGISTER:
+ ASSERT_RTNL();
list_for_each_entry(ops, &net->rules_ops, list)
attach_rules(&ops->rules_list, dev);
break;
case NETDEV_UNREGISTER:
+ ASSERT_RTNL();
list_for_each_entry(ops, &net->rules_ops, list)
detach_rules(&ops->rules_list, dev);
break;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 34d975b0f277..c64efcff8078 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2358,7 +2358,7 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
case NETDEV_PRE_TYPE_CHANGE:
case NETDEV_GOING_DOWN:
case NETDEV_UNREGISTER:
- case NETDEV_UNREGISTER_BATCH:
+ case NETDEV_UNREGISTER_FINAL:
case NETDEV_RELEASE:
case NETDEV_JOIN:
break;
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index adf273f8ad2e..6a5e6e4b142c 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1147,8 +1147,12 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = ptr;
- struct in_device *in_dev = __in_dev_get_rtnl(dev);
+ struct in_device *in_dev;
+ if (event == NETDEV_UNREGISTER_FINAL)
+ goto out;
+
+ in_dev = __in_dev_get_rtnl(dev);
ASSERT_RTNL();
if (!in_dev) {
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 7f073a38c87d..fd7d9ae64f16 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1041,7 +1041,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
- struct in_device *in_dev = __in_dev_get_rtnl(dev);
+ struct in_device *in_dev;
struct net *net = dev_net(dev);
if (event == NETDEV_UNREGISTER) {
@@ -1050,9 +1050,11 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
return NOTIFY_DONE;
}
- if (!in_dev)
+ if (event == NETDEV_UNREGISTER_FINAL)
return NOTIFY_DONE;
+ in_dev = __in_dev_get_rtnl(dev);
+
switch (event) {
case NETDEV_UP:
for_ifa(in_dev) {
@@ -1071,8 +1073,6 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
case NETDEV_CHANGE:
rt_cache_flush(dev_net(dev), 0);
break;
- case NETDEV_UNREGISTER_BATCH:
- break;
}
return NOTIFY_DONE;
}
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6bc85f7c31e3..e581009cb09e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2566,10 +2566,14 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
void *data)
{
struct net_device *dev = (struct net_device *) data;
- struct inet6_dev *idev = __in6_dev_get(dev);
+ struct inet6_dev *idev;
int run_pending = 0;
int err;
+ if (event == NETDEV_UNREGISTER_FINAL)
+ return NOTIFY_DONE;
+
+ idev = __in6_dev_get(dev);
switch (event) {
case NETDEV_REGISTER:
if (!idev && dev->mtu >= IPV6_MIN_MTU) {