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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  VFS: Fix race between CPU hotplug and lglocks
This commit is contained in:
Linus Torvalds 2011-12-23 21:47:28 -08:00
parent 6d451c578c e30e2fdfe5
commit a22681fabb
1 changed files with 32 additions and 4 deletions
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36
include/linux/lglock.h
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@ -22,6 +22,7 @@
#include <linux/spinlock.h>
#include <linux/lockdep.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
/* can make br locks by using local lock for read side, global lock for write */
#define br_lock_init(name) name##_lock_init()
@ -72,9 +73,31 @@
#define DEFINE_LGLOCK(name) \
\
DEFINE_SPINLOCK(name##_cpu_lock); \
cpumask_t name##_cpus __read_mostly; \
DEFINE_PER_CPU(arch_spinlock_t, name##_lock); \
DEFINE_LGLOCK_LOCKDEP(name); \
\
static int \
name##_lg_cpu_callback(struct notifier_block *nb, \
unsigned long action, void *hcpu) \
{ \
switch (action & ~CPU_TASKS_FROZEN) { \
case CPU_UP_PREPARE: \
spin_lock(&name##_cpu_lock); \
cpu_set((unsigned long)hcpu, name##_cpus); \
spin_unlock(&name##_cpu_lock); \
break; \
case CPU_UP_CANCELED: case CPU_DEAD: \
spin_lock(&name##_cpu_lock); \
cpu_clear((unsigned long)hcpu, name##_cpus); \
spin_unlock(&name##_cpu_lock); \
} \
return NOTIFY_OK; \
} \
static struct notifier_block name##_lg_cpu_notifier = { \
.notifier_call = name##_lg_cpu_callback, \
}; \
void name##_lock_init(void) { \
int i; \
LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
@ -83,6 +106,11 @@
lock = &per_cpu(name##_lock, i); \
*lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; \
} \
register_hotcpu_notifier(&name##_lg_cpu_notifier); \
get_online_cpus(); \
for_each_online_cpu(i) \
cpu_set(i, name##_cpus); \
put_online_cpus(); \
} \
EXPORT_SYMBOL(name##_lock_init); \
\
@ -124,9 +152,9 @@
\
void name##_global_lock_online(void) { \
int i; \
preempt_disable(); \
spin_lock(&name##_cpu_lock); \
rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \
for_each_online_cpu(i) { \
for_each_cpu(i, &name##_cpus) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_lock(lock); \
@ -137,12 +165,12 @@
void name##_global_unlock_online(void) { \
int i; \
rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \
for_each_online_cpu(i) { \
for_each_cpu(i, &name##_cpus) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_unlock(lock); \
} \
preempt_enable(); \
spin_unlock(&name##_cpu_lock); \
} \
EXPORT_SYMBOL(name##_global_unlock_online); \
\