Re: [PATCH v13 02/13] eventfd: Export eventfd_wake_count to modules
From: Jason Wang <hidden>
Date: 2021-09-01 02:52:06
Also in:
kvm, linux-fsdevel, linux-iommu, lkml, virtualization
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 <redacted>
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 <redacted>
quoted hunk ↗ jump to hunk
--- 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);