| Message ID | 20210831103634.33-3-xieyongji@bytedance.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce VDUSE - vDPA Device in Userspace | expand |
在 2021/8/31 下午6:36, Xie Yongji 写道: > Export eventfd_wake_count so that some modules can use > the eventfd_signal_count() to check whether the > eventfd_signal() call should be deferred to a safe context. > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com> And this matches the comment inside eventfd_signal(): /* * Deadlock or stack overflow issues can happen if we recurse here * through waitqueue wakeup handlers. If the caller users potentially * nested waitqueues with custom wakeup handlers, then it should * check eventfd_signal_count() before calling this function. If * it returns true, the eventfd_signal() call should be deferred to a * safe context. */ So: Acked-by: Jason Wang <jasowang@redhat.com> > --- > fs/eventfd.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/eventfd.c b/fs/eventfd.c > index e265b6dd4f34..1b3130b8d6c1 100644 > --- a/fs/eventfd.c > +++ b/fs/eventfd.c > @@ -26,6 +26,7 @@ > #include <linux/uio.h> > > DEFINE_PER_CPU(int, eventfd_wake_count); > +EXPORT_PER_CPU_SYMBOL_GPL(eventfd_wake_count); > > static DEFINE_IDA(eventfd_ida); >
diff --git a/fs/eventfd.c b/fs/eventfd.c index e265b6dd4f34..1b3130b8d6c1 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -26,6 +26,7 @@ #include <linux/uio.h> DEFINE_PER_CPU(int, eventfd_wake_count); +EXPORT_PER_CPU_SYMBOL_GPL(eventfd_wake_count); static DEFINE_IDA(eventfd_ida);
Export eventfd_wake_count so that some modules can use the eventfd_signal_count() to check whether the eventfd_signal() call should be deferred to a safe context. Signed-off-by: Xie Yongji <xieyongji@bytedance.com> --- fs/eventfd.c | 1 + 1 file changed, 1 insertion(+)