[PATCH review for 4.9 31/50] xen/manage: correct return value check on xenbus_scanf()

[Levin, Alexander (Sasha Levin)]

From: Jan Beulich <jbeul...@suse.com>

[ 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 <jbeul...@suse.com>
Reviewed-by: Juergen Gross <jgr...@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/xen/manage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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;
-- 
2.11.0