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cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()

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Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use
get_online_cpus and put_online_cpus instead as it highlights the
refcount semantics in these operations.

The new API guarantees protection against the cpu-hotplug operation, but
it doesn't guarantee serialized access to any of the local data
structures. Hence the changes needs to be reviewed.

In case of pseries_add_processor/pseries_remove_processor, use
cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the
cpu_present_map there.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Gautham R Shenoy
2008-01-25 21:08:02 +01:00
committed by Ingo Molnar
parent d221938c04
commit 86ef5c9a8e
15 changed files with 62 additions and 61 deletions
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8
include/linux/cpu.h
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@@ -100,8 +100,8 @@ static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
mutex_unlock(cpu_hp_mutex);
}
extern void lock_cpu_hotplug(void);
extern void unlock_cpu_hotplug(void);
extern void get_online_cpus(void);
extern void put_online_cpus(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \
@@ -118,8 +118,8 @@ static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
{ }
#define lock_cpu_hotplug() do { } while (0)
#define unlock_cpu_hotplug() do { } while (0)
#define get_online_cpus() do { } while (0)
#define put_online_cpus() do { } while (0)
#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
/* These aren't inline functions due to a GCC bug. */
#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })