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authorKusanagi Kouichi <slash@ac.auone-net.jp>2014-01-18 14:38:45 +0900
committerStefan Hajnoczi <stefanha@redhat.com>2014-01-27 15:44:06 +0100
commit1f149e721feb617d14a3ee4f5911c47b29866a54 (patch)
tree11d16f254b4a2a9610a767990d947e2865aa2e85 /net/tap-linux.c
parentc444dfabfc21cb5f093862100e333b808eea32e4 (diff)
downloadfocaccia-qemu-1f149e721feb617d14a3ee4f5911c47b29866a54.tar.gz
focaccia-qemu-1f149e721feb617d14a3ee4f5911c47b29866a54.zip
tap-linux: Get features once and use it many times
Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'net/tap-linux.c')
-rw-r--r--net/tap-linux.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/net/tap-linux.c b/net/tap-linux.c
index 36c09e24d8..812bf2dfc6 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -52,14 +52,17 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
     memset(&ifr, 0, sizeof(ifr));
     ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 
-    if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
-        features & IFF_ONE_QUEUE) {
+    if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
+        error_report("warning: TUNGETFEATURES failed: %s", strerror(errno));
+        features = 0;
+    }
+
+    if (features & IFF_ONE_QUEUE) {
         ifr.ifr_flags |= IFF_ONE_QUEUE;
     }
 
     if (*vnet_hdr) {
-        if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
-            features & IFF_VNET_HDR) {
+        if (features & IFF_VNET_HDR) {
             *vnet_hdr = 1;
             ifr.ifr_flags |= IFF_VNET_HDR;
         } else {
@@ -82,8 +85,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
     }
 
     if (mq_required) {
-        if ((ioctl(fd, TUNGETFEATURES, &features) != 0) ||
-            !(features & IFF_MULTI_QUEUE)) {
+        if (!(features & IFF_MULTI_QUEUE)) {
             error_report("multiqueue required, but no kernel "
                          "support for IFF_MULTI_QUEUE available");
             close(fd);