linux-kernel - [PATCH 12/12] xen: make use of xenbus_read

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Message-Id: <1477932510-28594-13-git-send-email-jgross@suse.com>
Date:   Mon, 31 Oct 2016 17:48:30 +0100
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xen.org
Cc:     david.vrabel@...rix.com, boris.ostrovsky@...cle.com,
        Juergen Gross <jgross@...e.com>
Subject: [PATCH 12/12] xen: make use of xenbus_read_unsigned() in xenbus

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 drivers/xen/xenbus/xenbus_probe_backend.c | 8 +-------
 drivers/xen/xenbus/xenbus_xs.c            | 7 +++----
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index 04f7f85..37929df 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -224,13 +224,7 @@ static int read_frontend_details(struct xenbus_device *xendev)
 
 int xenbus_dev_is_online(struct xenbus_device *dev)
 {
-	int rc, val;
-
-	rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
-	if (rc != 1)
-		val = 0; /* no online node present */
-
-	return val;
+	return !!xenbus_read_unsigned(dev->nodename, "online", 0);
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
 
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 99dfdfa..6afb993 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -687,7 +687,7 @@ static bool xen_strict_xenbus_quirk(void)
 }
 static void xs_reset_watches(void)
 {
-	int err, supported = 0;
+	int err;
 
 	if (!xen_hvm_domain() || xen_initial_domain())
 		return;
@@ -695,9 +695,8 @@ static void xs_reset_watches(void)
 	if (xen_strict_xenbus_quirk())
 		return;
 
-	err = xenbus_scanf(XBT_NIL, "control",
-			"platform-feature-xs_reset_watches", "%d", &supported);
-	if (err != 1 || !supported)
+	if (!xenbus_read_unsigned("control",
+				  "platform-feature-xs_reset_watches", 0))
 		return;
 
 	err = xs_error(xs_single(XBT_NIL, XS_RESET_WATCHES, "", NULL));
-- 
2.6.6