Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
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include/linux/lglock.h
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include/linux/lglock.h
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#include <linux/spinlock.h>
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#include <linux/lockdep.h>
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#include <linux/percpu.h>
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#include <linux/cpu.h>
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/* can make br locks by using local lock for read side, global lock for write */
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#define br_lock_init(name) name##_lock_init()
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#define DEFINE_LGLOCK(name) \
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\
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DEFINE_SPINLOCK(name##_cpu_lock); \
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cpumask_t name##_cpus __read_mostly; \
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DEFINE_PER_CPU(arch_spinlock_t, name##_lock); \
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DEFINE_LGLOCK_LOCKDEP(name); \
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\
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static int \
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name##_lg_cpu_callback(struct notifier_block *nb, \
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unsigned long action, void *hcpu) \
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{ \
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switch (action & ~CPU_TASKS_FROZEN) { \
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case CPU_UP_PREPARE: \
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spin_lock(&name##_cpu_lock); \
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cpu_set((unsigned long)hcpu, name##_cpus); \
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spin_unlock(&name##_cpu_lock); \
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break; \
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case CPU_UP_CANCELED: case CPU_DEAD: \
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spin_lock(&name##_cpu_lock); \
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cpu_clear((unsigned long)hcpu, name##_cpus); \
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spin_unlock(&name##_cpu_lock); \
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} \
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return NOTIFY_OK; \
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} \
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static struct notifier_block name##_lg_cpu_notifier = { \
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.notifier_call = name##_lg_cpu_callback, \
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}; \
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void name##_lock_init(void) { \
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int i; \
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LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
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lock = &per_cpu(name##_lock, i); \
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*lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; \
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} \
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register_hotcpu_notifier(&name##_lg_cpu_notifier); \
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get_online_cpus(); \
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for_each_online_cpu(i) \
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cpu_set(i, name##_cpus); \
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put_online_cpus(); \
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} \
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EXPORT_SYMBOL(name##_lock_init); \
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\
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\
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void name##_global_lock_online(void) { \
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int i; \
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preempt_disable(); \
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spin_lock(&name##_cpu_lock); \
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rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \
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for_each_online_cpu(i) { \
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for_each_cpu(i, &name##_cpus) { \
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arch_spinlock_t *lock; \
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lock = &per_cpu(name##_lock, i); \
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arch_spin_lock(lock); \
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void name##_global_unlock_online(void) { \
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int i; \
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rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \
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for_each_online_cpu(i) { \
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for_each_cpu(i, &name##_cpus) { \
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arch_spinlock_t *lock; \
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lock = &per_cpu(name##_lock, i); \
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arch_spin_unlock(lock); \
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} \
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preempt_enable(); \
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spin_unlock(&name##_cpu_lock); \
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} \
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EXPORT_SYMBOL(name##_global_unlock_online); \
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\