Basic helper that copies ready events to the specified userspace
address. The event checking is quick and racy, it's up to the caller
to ensure it retries appropriately in case 0 events are copied.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/eventpoll.c | 20 ++++++++++++++++++++
include/linux/eventpoll.h | 4 ++++
2 files changed, 24 insertions(+)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 14466765b85d..94b87aaad0f6 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2474,6 +2474,26 @@ static int ep_check_params(struct file *file, struct epoll_event __user *evs,
return 0;
}
+int epoll_sendevents(struct file *file, struct epoll_event __user *events,
+ int maxevents)
+{
+ struct eventpoll *ep;
+ int ret;
+
+ ret = ep_check_params(file, events, maxevents);
+ if (unlikely(ret))
+ return ret;
+
+ ep = file->private_data;
+ /*
+ * Racy call, but that's ok - it should get retried based on
+ * poll readiness anyway.
+ */
+ if (ep_events_available(ep))
+ return ep_try_send_events(ep, events, maxevents);
+ return 0;
+}
+
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_wait(2).
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 0c0d00fcd131..ccb478eb174b 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -25,6 +25,10 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long t
/* Used to release the epoll bits inside the "struct file" */
void eventpoll_release_file(struct file *file);
+/* Copy ready events to userspace */
+int epoll_sendevents(struct file *file, struct epoll_event __user *events,
+ int maxevents);
+
/*
* This is called from inside fs/file_table.c:__fput() to unlink files
* from the eventpoll interface. We need to have this facility to cleanup
--
2.47.2
