From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Thu, 14 Oct 2010 18:38:47 +0000 (-0700)
Subject: xen/hvc: only notify if we actually sent something
X-Git-Tag: v2.6.37-rc1~93^3~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=403a85ff001710bb92689790b9a5c1c80e4b37a6;p=thirdparty%2Flinux.git

xen/hvc: only notify if we actually sent something

Don't spam dom0/xenconsoled with events unless we've actually added
something to the ring.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---

diff --git a/drivers/char/hvc_xen.c b/drivers/char/hvc_xen.c
index 60446f82a3fc2..6b8e6d18a8e6e 100644
--- a/drivers/char/hvc_xen.c
+++ b/drivers/char/hvc_xen.c
@@ -74,7 +74,8 @@ static int __write_console(const char *data, int len)
 	wmb();			/* write ring before updating pointer */
 	intf->out_prod = prod;
 
-	notify_daemon();
+	if (sent)
+		notify_daemon();
 	return sent;
 }