path: root/include
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authorLinus Torvalds <torvalds@macmini.osdl.org>2006-07-23 12:12:16 -0700
committerLinus Torvalds <torvalds@macmini.osdl.org>2006-07-23 12:12:16 -0700
commitaa95387774039096c11803c04011f1aa42d85758 (patch)
treeb8d3c845efedc2d67bcaff0038b4306fa375379c /include
parent2cd7cbdf4bd0d0fe58e4dc903e8b413412595504 (diff)
cpu hotplug: simplify and hopefully fix locking
The CPU hotplug locking was quite messy, with a recursive lock to handle the fact that both the actual up/down sequence wanted to protect itself from being re-entered, but the callbacks that it called also tended to want to protect themselves from CPU events. This splits the lock into two (one to serialize the whole hotplug sequence, the other to protect against the CPU present bitmaps changing). The latter still allows recursive usage because some subsystems (ondemand policy for cpufreq at least) had already gotten too used to the lax locking, but the locking mistakes are hopefully now less fundamental, and we now warn about recursive lock usage when we see it, in the hope that it can be fixed. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
1 files changed, 0 insertions, 6 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 44a11f1ccaf2..8fb344a9abd8 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -48,7 +48,6 @@ static inline void unregister_cpu_notifier(struct notifier_block *nb)
-extern int current_in_cpu_hotplug(void);
int cpu_up(unsigned int cpu);
@@ -61,10 +60,6 @@ static inline int register_cpu_notifier(struct notifier_block *nb)
static inline void unregister_cpu_notifier(struct notifier_block *nb)
-static inline int current_in_cpu_hotplug(void)
- return 0;
#endif /* CONFIG_SMP */
extern struct sysdev_class cpu_sysdev_class;
@@ -73,7 +68,6 @@ extern struct sysdev_class cpu_sysdev_class;
/* Stop CPUs going up and down. */
extern void lock_cpu_hotplug(void);
extern void unlock_cpu_hotplug(void);
-extern int lock_cpu_hotplug_interruptible(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \

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