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* [PATCH] xen-netback: correct return value checks on xenbus_scanf()
@ 2016-07-07  7:57 Jan Beulich
  2016-07-07  8:26 ` [Xen-devel] " Paul Durrant
  2016-07-07  9:58 ` David Vrabel
  0 siblings, 2 replies; 9+ messages in thread
From: Jan Beulich @ 2016-07-07  7:57 UTC (permalink / raw)
  To: Wei Liu; +Cc: xen-devel, netdev

Only a positive return value indicates success.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
 drivers/net/xen-netback/xenbus.c |   26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

--- 4.7-rc6-xenbus_scanf.orig/drivers/net/xen-netback/xenbus.c
+++ 4.7-rc6-xenbus_scanf/drivers/net/xen-netback/xenbus.c
@@ -741,7 +741,7 @@ static void xen_mcast_ctrl_changed(struc
 	int val;
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend,
-			 "request-multicast-control", "%d", &val) < 0)
+			 "request-multicast-control", "%d", &val) <= 0)
 		val = 0;
 	vif->multicast_control = !!val;
 }
@@ -890,7 +890,7 @@ static void connect(struct backend_info
 	err = xenbus_scanf(XBT_NIL, dev->otherend,
 			   "multi-queue-num-queues",
 			   "%u", &requested_num_queues);
-	if (err < 0) {
+	if (err <= 0) {
 		requested_num_queues = 1; /* Fall back to single queue */
 	} else if (requested_num_queues > xenvif_max_queues) {
 		/* buggy or malicious guest */
@@ -1056,7 +1056,7 @@ static int connect_data_rings(struct bac
 	if (err < 0) {
 		err = xenbus_scanf(XBT_NIL, xspath,
 				   "event-channel", "%u", &tx_evtchn);
-		if (err < 0) {
+		if (err <= 0) {
 			xenbus_dev_fatal(dev, err,
 					 "reading %s/event-channel(-tx/rx)",
 					 xspath);
@@ -1092,10 +1092,10 @@ static int read_xenbus_vif_flags(struct
 	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
 			   &rx_copy);
 	if (err == -ENOENT) {
-		err = 0;
+		err = 1;
 		rx_copy = 0;
 	}
-	if (err < 0) {
+	if (err <= 0) {
 		xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
 				 dev->otherend);
 		return err;
@@ -1104,7 +1104,7 @@ static int read_xenbus_vif_flags(struct
 		return -EOPNOTSUPP;
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend,
-			 "feature-rx-notify", "%d", &val) < 0)
+			 "feature-rx-notify", "%d", &val) <= 0)
 		val = 0;
 	if (!val) {
 		/* - Reduce drain timeout to poll more frequently for
@@ -1116,7 +1116,7 @@ static int read_xenbus_vif_flags(struct
 	}
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	vif->can_sg = !!val;
 
@@ -1124,25 +1124,25 @@ static int read_xenbus_vif_flags(struct
 	vif->gso_prefix_mask = 0;
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	if (val)
 		vif->gso_mask |= GSO_BIT(TCPV4);
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	if (val)
 		vif->gso_prefix_mask |= GSO_BIT(TCPV4);
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	if (val)
 		vif->gso_mask |= GSO_BIT(TCPV6);
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6-prefix",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	if (val)
 		vif->gso_prefix_mask |= GSO_BIT(TCPV6);
@@ -1156,12 +1156,12 @@ static int read_xenbus_vif_flags(struct
 	}
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	vif->ip_csum = !val;
 
 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
-			 "%d", &val) < 0)
+			 "%d", &val) <= 0)
 		val = 0;
 	vif->ipv6_csum = !!val;
 

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2016-07-07 12:21 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-07-07  7:57 [PATCH] xen-netback: correct return value checks on xenbus_scanf() Jan Beulich
2016-07-07  8:26 ` [Xen-devel] " Paul Durrant
2016-07-07  9:58 ` David Vrabel
2016-07-07 10:35   ` Wei Liu
2016-07-07 10:40     ` Paul Durrant
2016-07-07 10:42     ` Paul Durrant
2016-07-07 10:45     ` David Vrabel
2016-07-07 10:55       ` Paul Durrant
2016-07-07 12:21         ` Jan Beulich

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