Extract the no_poll() and vop_nopoll() code into the common routine

poll_no_poll().
Return a poll_no_poll() result from devfs_poll_f() when
filedescriptor does not reference the live cdev, instead of ENXIO.

Noted and tested by:	hps
MFC after:	1 week

3 files changed, 18 insertions, 22 deletions

diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index fb18b34..3ef55ea 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -312,18 +312,8 @@ no_strategy(struct bio *bp)
 static int
 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
 {
-	/*
-	 * Return true for read/write.  If the user asked for something
-	 * special, return POLLNVAL, so that clients have a way of
-	 * determining reliably whether or not the extended
-	 * functionality is present without hard-coding knowledge
-	 * of specific filesystem implementations.
-	 * Stay in sync with vop_nopoll().
-	 */
-	if (events & ~POLLSTANDARD)
-		return (POLLNVAL);
 
-	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
+	return (poll_no_poll(events));
 }
 
 #define no_dump		(dumper_t *)enodev
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 3209610..ad7c32e 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -731,6 +731,22 @@ out:
 	return (error);
 }
 
+int
+poll_no_poll(int events)
+{
+	/*
+	 * Return true for read/write.  If the user asked for something
+	 * special, return POLLNVAL, so that clients have a way of
+	 * determining reliably whether or not the extended
+	 * functionality is present without hard-coding knowledge
+	 * of specific filesystem implementations.
+	 */
+	if (events & ~POLLSTANDARD)
+		return (POLLNVAL);
+
+	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
+}
+
 #ifndef _SYS_SYSPROTO_H_
 struct select_args {
 	int	nd;
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index a3f3725..e047a90 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -354,18 +354,8 @@ vop_nopoll(ap)
 		struct thread *a_td;
 	} */ *ap;
 {
-	/*
-	 * Return true for read/write.  If the user asked for something
-	 * special, return POLLNVAL, so that clients have a way of
-	 * determining reliably whether or not the extended
-	 * functionality is present without hard-coding knowledge
-	 * of specific filesystem implementations.
-	 * Stay in sync with kern_conf.c::no_poll().
-	 */
-	if (ap->a_events & ~POLLSTANDARD)
-		return (POLLNVAL);
 
-	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
+	return (poll_no_poll(ap->a_events));
 }
 
 /*