From 41f63c5359d14ca995172b8f6eaffd93f60fec54 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Aug 2012 10:30:47 -0700 Subject: workqueue: use mod_delayed_work() instead of cancel + queue Convert delayed_work users doing cancel_delayed_work() followed by queue_delayed_work() to mod_delayed_work(). Most conversions are straight-forward. Ones worth mentioning are, * drivers/edac/edac_mc.c: edac_mc_workq_setup() converted to always use mod_delayed_work() and cancel loop in edac_mc_reset_delay_period() is dropped. * drivers/platform/x86/thinkpad_acpi.c: No need to remember whether watchdog is active or not. @fan_watchdog_active and related code dropped. * drivers/power/charger-manager.c: Seemingly a lot of delayed_work_pending() abuse going on here. [delayed_]work_pending() are unsynchronized and racy when used like this. I converted one instance in fullbatt_handler(). Please conver the rest so that it invokes workqueue APIs for the intended target state rather than trying to game work item pending state transitions. e.g. if timer should be modified - call mod_delayed_work(), canceled - call cancel_delayed_work[_sync](). * drivers/thermal/thermal_sys.c: thermal_zone_device_set_polling() simplified. Note that round_jiffies() calls in this function are meaningless. round_jiffies() work on absolute jiffies not delta delay used by delayed_work. v2: Tomi pointed out that __cancel_delayed_work() users can't be safely converted to mod_delayed_work(). They could be calling it from irq context and if that happens while delayed_work_timer_fn() is running, it could deadlock. __cancel_delayed_work() users are dropped. Signed-off-by: Tejun Heo Acked-by: Henrique de Moraes Holschuh Acked-by: Dmitry Torokhov Acked-by: Anton Vorontsov Acked-by: David Howells Cc: Tomi Valkeinen Cc: Jens Axboe Cc: Jiri Kosina Cc: Doug Thompson Cc: David Airlie Cc: Roland Dreier Cc: "John W. Linville" Cc: Zhang Rui Cc: Len Brown Cc: "J. Bruce Fields" Cc: Johannes Berg --- net/core/dst.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/core/dst.c') diff --git a/net/core/dst.c b/net/core/dst.c index 069d51d29414..ed5a0b409aa3 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -214,8 +214,8 @@ void __dst_free(struct dst_entry *dst) if (dst_garbage.timer_inc > DST_GC_INC) { dst_garbage.timer_inc = DST_GC_INC; dst_garbage.timer_expires = DST_GC_MIN; - cancel_delayed_work(&dst_gc_work); - schedule_delayed_work(&dst_gc_work, dst_garbage.timer_expires); + mod_delayed_work(system_wq, &dst_gc_work, + dst_garbage.timer_expires); } spin_unlock_bh(&dst_garbage.lock); } -- cgit v1.2.3 From 0115e8e30d6fcdd4b8faa30d3ffd90859a591f51 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 22 Aug 2012 17:19:46 +0000 Subject: 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 Cc: Tom Herbert Cc: Mahesh Bandewar Cc: "Eric W. Biederman" Cc: Gao feng Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 +- net/core/dev.c | 22 ++++++++-------------- net/core/dst.c | 2 +- net/core/fib_rules.c | 3 ++- net/core/rtnetlink.c | 2 +- net/ipv4/devinet.c | 6 +++++- net/ipv4/fib_frontend.c | 8 ++++---- net/ipv6/addrconf.c | 6 +++++- 8 files changed, 27 insertions(+), 24 deletions(-) (limited to 'net/core/dst.c') 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) { -- cgit v1.2.3