From: Jan Beulich <JBeulich@suse.com>
Date: Sat, 7 Oct 2017 22:36:53 +0000 (+0000)
Subject: xen/manage: correct return value check on xenbus_scanf()
X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~7^2~1460
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b469d5c393c24a3b1edb3c88e61d2d8c1bc0a38a;p=linux-4.9.git

xen/manage: correct return value check on xenbus_scanf()


[ Upstream commit 4fed1b125eb6252bde478665fc05d4819f774fa8 ]

A negative return value indicates an error; in fact the function at
present won't ever return zero.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 26e5e8507f03..357a8db859c9 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -277,7 +277,7 @@ static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
 	err = xenbus_transaction_start(&xbt);
 	if (err)
 		return;
-	if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
+	if (xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key) < 0) {
 		pr_err("Unable to read sysrq code in control/sysrq\n");
 		xenbus_transaction_end(xbt, 1);
 		return;