xen: make use of xenbus_read_unsigned() in xen-netback
Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.
Cc: wei.liu2@citrix.com
Cc: paul.durrant@citrix.com
Cc: netdev@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 8674e18..7356e00 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -785,12 +785,9 @@ static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
struct xenvif *vif = container_of(watch, struct xenvif,
mcast_ctrl_watch);
struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
- int val;
- if (xenbus_scanf(XBT_NIL, dev->otherend,
- "request-multicast-control", "%d", &val) < 0)
- val = 0;
- vif->multicast_control = !!val;
+ vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
+ "request-multicast-control", 0);
}
static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
@@ -934,12 +931,9 @@ static void connect(struct backend_info *be)
/* Check whether the frontend requested multiple queues
* and read the number requested.
*/
- err = xenbus_scanf(XBT_NIL, dev->otherend,
- "multi-queue-num-queues",
- "%u", &requested_num_queues);
- if (err < 0) {
- requested_num_queues = 1; /* Fall back to single queue */
- } else if (requested_num_queues > xenvif_max_queues) {
+ requested_num_queues = xenbus_read_unsigned(dev->otherend,
+ "multi-queue-num-queues", 1);
+ if (requested_num_queues > xenvif_max_queues) {
/* buggy or malicious guest */
xenbus_dev_fatal(dev, err,
"guest requested %u queues, exceeding the maximum of %u.",
@@ -1134,7 +1128,7 @@ static int read_xenbus_vif_flags(struct backend_info *be)
struct xenvif *vif = be->vif;
struct xenbus_device *dev = be->dev;
unsigned int rx_copy;
- int err, val;
+ int err;
err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
&rx_copy);
@@ -1150,10 +1144,7 @@ static int read_xenbus_vif_flags(struct backend_info *be)
if (!rx_copy)
return -EOPNOTSUPP;
- if (xenbus_scanf(XBT_NIL, dev->otherend,
- "feature-rx-notify", "%d", &val) < 0)
- val = 0;
- if (!val) {
+ if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
/* - Reduce drain timeout to poll more frequently for
* Rx requests.
* - Disable Rx stall detection.
@@ -1162,34 +1153,21 @@ static int read_xenbus_vif_flags(struct backend_info *be)
be->vif->stall_timeout = 0;
}
- if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
- "%d", &val) < 0)
- val = 0;
- vif->can_sg = !!val;
+ vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
vif->gso_mask = 0;
- if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
- "%d", &val) < 0)
- val = 0;
- if (val)
+ if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
vif->gso_mask |= GSO_BIT(TCPV4);
- if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
- "%d", &val) < 0)
- val = 0;
- if (val)
+ if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
vif->gso_mask |= GSO_BIT(TCPV6);
- if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
- "%d", &val) < 0)
- val = 0;
- vif->ip_csum = !val;
+ vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
+ "feature-no-csum-offload", 0);
- if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
- "%d", &val) < 0)
- val = 0;
- vif->ipv6_csum = !!val;
+ vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
+ "feature-ipv6-csum-offload", 0);
return 0;
}