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linux-next/kernel/user-return-notifier.c
Avi Kivity 1786bf009f core: Clean up user return notifers use of per_cpu
Instead of using per_cpu(..., raw_smp_processor_id()), use
__get_cpu_var(...).

Signed-off-by: Avi Kivity <avi@redhat.com>
LKML-Reference: <1259578491-4589-1-git-send-email-avi@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-02 10:22:59 +01:00

45 lines
1.3 KiB
C

#include <linux/user-return-notifier.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/module.h>
static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
/*
* Request a notification when the current cpu returns to userspace. Must be
* called in atomic context. The notifier will also be called in atomic
* context.
*/
void user_return_notifier_register(struct user_return_notifier *urn)
{
set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
hlist_add_head(&urn->link, &__get_cpu_var(return_notifier_list));
}
EXPORT_SYMBOL_GPL(user_return_notifier_register);
/*
* Removes a registered user return notifier. Must be called from atomic
* context, and from the same cpu registration occured in.
*/
void user_return_notifier_unregister(struct user_return_notifier *urn)
{
hlist_del(&urn->link);
if (hlist_empty(&__get_cpu_var(return_notifier_list)))
clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
}
EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
/* Calls registered user return notifiers */
void fire_user_return_notifiers(void)
{
struct user_return_notifier *urn;
struct hlist_node *tmp1, *tmp2;
struct hlist_head *head;
head = &get_cpu_var(return_notifier_list);
hlist_for_each_entry_safe(urn, tmp1, tmp2, head, link)
urn->on_user_return(urn);
put_cpu_var(return_notifier_list);
}