Provide a new interface for the user of aio_read() and aio_write() to request

a kevent upon completion of the I/O.  Specifically, introduce a new type
of sigevent notification, SIGEV_EVENT.  If sigev_notify is SIGEV_EVENT,
then sigev_notify_kqueue names the kqueue that should receive the event
and sigev_value contains the "void *" is copied into the kevent's udata
field.

In contrast to the existing interface, this one: 1) works on
the Alpha 2) avoids the extra copyin() call for the kevent because all
of the information needed is in the sigevent and 3) could be
applied to request a single kevent upon completion of an entire lio_listio().

Reviewed by:	jlemon

1 files changed, 7 insertions, 1 deletions

diff --git a/sys/sys/_sigset.h b/sys/sys/_sigset.h
index e3bef902d77a..95891ffd78bc 100644
--- a/sys/sys/_sigset.h
+++ b/sys/sys/_sigset.h
@@ -133,12 +133,18 @@ union sigval {
 
 struct sigevent {
 	int	sigev_notify;		/* Notification type */
-	int	sigev_signo;		/* Signal number */
+	union {
+		int	__sigev_signo;	/* Signal number */
+		int	__sigev_notify_kqueue;
+	} __sigev_u;
 	union sigval sigev_value;	/* Signal value */
 };
+#define sigev_signo		__sigev_u.__sigev_signo
+#define sigev_notify_kqueue	__sigev_u.__sigev_notify_kqueue
 
 #define	SIGEV_NONE	0		/* No async notification */
 #define	SIGEV_SIGNAL	1		/* Generate a queued signal */
+#define SIGEV_KEVENT	3		/* Generate a kevent */
 
 typedef struct __siginfo {
 	int	si_signo;		/* signal number */