From eff722b06bdd6de326894ea2353ec0eda3e5ed34 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 11 Mar 2014 02:04:45 +0530 Subject: ia64, salinfo: Fix hotplug callback registration Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the salinfo code in ia64 by using this latter form of callback registration. Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- arch/ia64/kernel/salinfo.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/salinfo.c b/arch/ia64/kernel/salinfo.c index 960a396f5929..ee9719eebb1e 100644 --- a/arch/ia64/kernel/salinfo.c +++ b/arch/ia64/kernel/salinfo.c @@ -635,6 +635,8 @@ salinfo_init(void) (void *)salinfo_entries[i].feature); } + cpu_notifier_register_begin(); + for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) { data = salinfo_data + i; data->type = i; @@ -669,7 +671,9 @@ salinfo_init(void) salinfo_timer.function = &salinfo_timeout; add_timer(&salinfo_timer); - register_hotcpu_notifier(&salinfo_cpu_notifier); + __register_hotcpu_notifier(&salinfo_cpu_notifier); + + cpu_notifier_register_done(); return 0; } -- cgit v1.2.3 From 9f37bca9a9e97fcd7589492aba7b8a5310026c47 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 11 Mar 2014 02:04:52 +0530 Subject: ia64, palinfo: Fix CPU hotplug callback registration Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the palinfo code in ia64 by using this latter form of callback registration. Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- arch/ia64/kernel/palinfo.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c index ab333284f4b2..c39c3cd3ac34 100644 --- a/arch/ia64/kernel/palinfo.c +++ b/arch/ia64/kernel/palinfo.c @@ -996,13 +996,17 @@ palinfo_init(void) if (!palinfo_dir) return -ENOMEM; + cpu_notifier_register_begin(); + /* Create palinfo dirs in /proc for all online cpus */ for_each_online_cpu(i) { create_palinfo_proc_entries(i); } /* Register for future delivery via notify registration */ - register_hotcpu_notifier(&palinfo_cpu_notifier); + __register_hotcpu_notifier(&palinfo_cpu_notifier); + + cpu_notifier_register_done(); return 0; } -- cgit v1.2.3 From f5a7d445ffb6b251dc41942ffe41f515e8d639a4 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 11 Mar 2014 02:04:58 +0530 Subject: ia64, topology: Fix CPU hotplug callback registration Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the topology code in ia64 by using this latter form of callback registration. Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- arch/ia64/kernel/topology.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c index ca69a5a96dcc..f295f9abba4b 100644 --- a/arch/ia64/kernel/topology.c +++ b/arch/ia64/kernel/topology.c @@ -454,12 +454,16 @@ static int __init cache_sysfs_init(void) { int i; + cpu_notifier_register_begin(); + for_each_online_cpu(i) { struct device *sys_dev = get_cpu_device((unsigned int)i); cache_add_dev(sys_dev); } - register_hotcpu_notifier(&cache_cpu_notifier); + __register_hotcpu_notifier(&cache_cpu_notifier); + + cpu_notifier_register_done(); return 0; } -- cgit v1.2.3 From f2e48a89053dea259d7f96cf0fd1cfc7c4b34d80 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 11 Mar 2014 02:05:10 +0530 Subject: ia64, err-inject: Fix CPU hotplug callback registration Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the error injection code in ia64 by using this latter form of callback registration. Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- arch/ia64/kernel/err_inject.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c index f59c0b844e88..0c161ed6d18e 100644 --- a/arch/ia64/kernel/err_inject.c +++ b/arch/ia64/kernel/err_inject.c @@ -269,12 +269,17 @@ err_inject_init(void) #ifdef ERR_INJ_DEBUG printk(KERN_INFO "Enter error injection driver.\n"); #endif + + cpu_notifier_register_begin(); + for_each_online_cpu(i) { err_inject_cpu_callback(&err_inject_cpu_notifier, CPU_ONLINE, (void *)(long)i); } - register_hotcpu_notifier(&err_inject_cpu_notifier); + __register_hotcpu_notifier(&err_inject_cpu_notifier); + + cpu_notifier_register_done(); return 0; } @@ -288,11 +293,17 @@ err_inject_exit(void) #ifdef ERR_INJ_DEBUG printk(KERN_INFO "Exit error injection driver.\n"); #endif + + cpu_notifier_register_begin(); + for_each_online_cpu(i) { sys_dev = get_cpu_device(i); sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group); } - unregister_hotcpu_notifier(&err_inject_cpu_notifier); + + __unregister_hotcpu_notifier(&err_inject_cpu_notifier); + + cpu_notifier_register_done(); } module_init(err_inject_init); -- cgit v1.2.3