From 9647155ffbce9dffed8a9a4768c8994334b609db Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Tue, 29 Apr 2008 00:58:48 -0700 Subject: cpu: fix section mismatch warning in unregister_cpu_notifier Fix following warning: WARNING: vmlinux.o(.text+0x75f4e): Section mismatch in reference from the function unregister_cpu_notifier() to the variable .cpuinit.data:cpu_chain We know that unregister_cpu_notifier is using HOTPLUG_CPU stuff - so ignore these references. Annotating unregister_cpu_notifier had been another option but this caused far more warnings since not all callers were annotated __cpuinit. Signed-off-by: Sam Ravnborg Cc: Gautham R Shenoy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/cpu.c') diff --git a/kernel/cpu.c b/kernel/cpu.c index 2011ad8d2697..da31165fd298 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -149,7 +149,7 @@ int __cpuinit register_cpu_notifier(struct notifier_block *nb) EXPORT_SYMBOL(register_cpu_notifier); -void unregister_cpu_notifier(struct notifier_block *nb) +void __ref unregister_cpu_notifier(struct notifier_block *nb) { cpu_maps_update_begin(); raw_notifier_chain_unregister(&cpu_chain, nb); -- cgit v1.2.2 From 514a20a5da99aef8e667cc395841a5c4e5f9e8c1 Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Tue, 29 Apr 2008 00:58:50 -0700 Subject: cpu: fix section mismatch warnings in *cpu_down Fix following warnings: WARNING: vmlinux.o(.text+0x75c8d): Section mismatch in reference from the function take_cpu_down() to the variable .cpuinit.data:cpu_chain WARNING: vmlinux.o(.text+0x75d2a): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain WARNING: vmlinux.o(.text+0x75d4d): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain WARNING: vmlinux.o(.text+0x75de4): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain WARNING: vmlinux.o(.text+0x75e33): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain cpu_down is only used from code surrounded by HOTPLUG_CPU so any references to __cpuinit is OK. Add a few __ref to tech modpost to ignore the references. This is just papering over the fact that the cpu hotplug code is fragile with respect to use of HOTPLUG_CPU and in many cases rely on __cpuinit to get rid of code when HOTPLUG_CPU is not enabled. For now this is the least invasive change. Signed-off-by: Sam Ravnborg Cc: Gautham R Shenoy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/cpu.c') diff --git a/kernel/cpu.c b/kernel/cpu.c index da31165fd298..306844ed58f7 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -180,7 +180,7 @@ struct take_cpu_down_param { }; /* Take this CPU down. */ -static int take_cpu_down(void *_param) +static int __ref take_cpu_down(void *_param) { struct take_cpu_down_param *param = _param; int err; @@ -199,7 +199,7 @@ static int take_cpu_down(void *_param) } /* Requires cpu_add_remove_lock to be held */ -static int _cpu_down(unsigned int cpu, int tasks_frozen) +static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) { int err, nr_calls = 0; struct task_struct *p; @@ -274,7 +274,7 @@ out_release: return err; } -int cpu_down(unsigned int cpu) +int __ref cpu_down(unsigned int cpu) { int err = 0; -- cgit v1.2.2 From f7b16c108fd044adc422ff21b5d6c16022462fd0 Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Tue, 29 Apr 2008 00:58:51 -0700 Subject: cpu: fix section mismatch warning in reference to register_cpu_notifier Fix following warnings: WARNING: vmlinux.o(.text+0xc60): Section mismatch in reference from the function kvm_init() to the function .cpuinit.text:register_cpu_notifier() WARNING: vmlinux.o(.text+0x33869a): Section mismatch in reference from the function xfs_icsb_init_counters() to the function .cpuinit.text:register_cpu_notifier() WARNING: vmlinux.o(.text+0x5556a1): Section mismatch in reference from the function acpi_processor_install_hotplug_notify() to the function .cpuinit.text:register_cpu_notifier() WARNING: vmlinux.o(.text+0xfe6b28): Section mismatch in reference from the function cpufreq_register_driver() to the function .cpuinit.text:register_cpu_notifier() register_cpu_notifier() are only really defined when HOTPLUG_CPU is enabled. So references to the function are OK. Annotate it with __ref so we do not get warnings from callers and do not get warnings for the functions/data used by register_cpu_notifier(). Signed-off-by: Sam Ravnborg Cc: Gautham R Shenoy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/cpu.c') diff --git a/kernel/cpu.c b/kernel/cpu.c index 306844ed58f7..f8f9468d17d7 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -136,7 +136,7 @@ static void cpu_hotplug_done(void) mutex_unlock(&cpu_hotplug.lock); } /* Need to know about CPUs going up/down? */ -int __cpuinit register_cpu_notifier(struct notifier_block *nb) +int __ref register_cpu_notifier(struct notifier_block *nb) { int ret; cpu_maps_update_begin(); -- cgit v1.2.2 From d2ba7e2ae206e9ab24e8937d99d0d5513bfd08e5 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 29 Apr 2008 01:00:29 -0700 Subject: simplify cpu_hotplug_begin()/put_online_cpus() cpu_hotplug_begin() must be always called under cpu_add_remove_lock, this means that only one process can be cpu_hotplug.active_writer. So we don't need the cpu_hotplug.writer_queue, we can wake up the ->active_writer directly. Also, fix the comment. Signed-off-by: Oleg Nesterov Cc: Dipankar Sarma Acked-by: Gautham R Shenoy Cc: Ingo Molnar Cc: Srivatsa Vaddagiri Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) (limited to 'kernel/cpu.c') diff --git a/kernel/cpu.c b/kernel/cpu.c index f8f9468d17d7..a98f6ab16ecd 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -33,17 +33,13 @@ static struct { * an ongoing cpu hotplug operation. */ int refcount; - wait_queue_head_t writer_queue; } cpu_hotplug; -#define writer_exists() (cpu_hotplug.active_writer != NULL) - void __init cpu_hotplug_init(void) { cpu_hotplug.active_writer = NULL; mutex_init(&cpu_hotplug.lock); cpu_hotplug.refcount = 0; - init_waitqueue_head(&cpu_hotplug.writer_queue); } #ifdef CONFIG_HOTPLUG_CPU @@ -65,11 +61,8 @@ void put_online_cpus(void) if (cpu_hotplug.active_writer == current) return; mutex_lock(&cpu_hotplug.lock); - cpu_hotplug.refcount--; - - if (unlikely(writer_exists()) && !cpu_hotplug.refcount) - wake_up(&cpu_hotplug.writer_queue); - + if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer)) + wake_up_process(cpu_hotplug.active_writer); mutex_unlock(&cpu_hotplug.lock); } @@ -98,8 +91,8 @@ void cpu_maps_update_done(void) * Note that during a cpu-hotplug operation, the new readers, if any, * will be blocked by the cpu_hotplug.lock * - * Since cpu_maps_update_begin is always called after invoking - * cpu_maps_update_begin, we can be sure that only one writer is active. + * Since cpu_hotplug_begin() is always called after invoking + * cpu_maps_update_begin(), we can be sure that only one writer is active. * * Note that theoretically, there is a possibility of a livelock: * - Refcount goes to zero, last reader wakes up the sleeping @@ -115,19 +108,16 @@ void cpu_maps_update_done(void) */ static void cpu_hotplug_begin(void) { - DECLARE_WAITQUEUE(wait, current); - - mutex_lock(&cpu_hotplug.lock); - cpu_hotplug.active_writer = current; - add_wait_queue_exclusive(&cpu_hotplug.writer_queue, &wait); - while (cpu_hotplug.refcount) { - set_current_state(TASK_UNINTERRUPTIBLE); + + for (;;) { + mutex_lock(&cpu_hotplug.lock); + if (likely(!cpu_hotplug.refcount)) + break; + __set_current_state(TASK_UNINTERRUPTIBLE); mutex_unlock(&cpu_hotplug.lock); schedule(); - mutex_lock(&cpu_hotplug.lock); } - remove_wait_queue_locked(&cpu_hotplug.writer_queue, &wait); } static void cpu_hotplug_done(void) -- cgit v1.2.2 From af1f16d08f38ab6f17b5760e6ec9d2b7d3a5ff1a Mon Sep 17 00:00:00 2001 From: Harvey Harrison Date: Wed, 30 Apr 2008 00:55:08 -0700 Subject: kernel: replace remaining __FUNCTION__ occurrences __FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/cpu.c') diff --git a/kernel/cpu.c b/kernel/cpu.c index a98f6ab16ecd..c77bc3a1c722 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -215,7 +215,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); printk("%s: attempt to take down CPU %u failed\n", - __FUNCTION__, cpu); + __func__, cpu); err = -EINVAL; goto out_release; } @@ -295,7 +295,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen) if (ret == NOTIFY_BAD) { nr_calls--; printk("%s: attempt to bring up CPU %u failed\n", - __FUNCTION__, cpu); + __func__, cpu); ret = -EINVAL; goto out_notify; } -- cgit v1.2.2