From: Ben Pfaff <blp@nicira.com>
Date: Mon, 29 Apr 2013 21:34:57 +0000 (-0700)
Subject: netdev-linux: Work on thread safety.
X-Git-Tag: sliver-openvswitch-2.0.90-1~34^2~54
X-Git-Url: http://git.onelab.eu/?a=commitdiff_plain;h=238821156596c227f4a32a8c3c4ad891591a1802;hp=954b526eed5eb2822b38ea6078bfee26c02c220e;p=sliver-openvswitch.git

netdev-linux: Work on thread safety.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
---

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 05877c1a4..e1ad4c863 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -1340,11 +1340,13 @@ static int
 netdev_linux_sys_get_stats(const struct netdev *netdev_,
                          struct netdev_stats *stats)
 {
-    static int use_netlink_stats = -1;
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+    static int use_netlink_stats;
     int error;
 
-    if (use_netlink_stats < 0) {
+    if (ovsthread_once_start(&once)) {
         use_netlink_stats = check_for_working_netlink_stats();
+        ovsthread_once_done(&once);
     }
 
     if (use_netlink_stats) {
@@ -3777,30 +3779,35 @@ read_psched(void)
      * [5] 2.6.32.21.22 (approx.) from Ubuntu 10.04 on VMware Fusion
      * [6] 2.6.34 from kernel.org on KVM
      */
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
     static const char fn[] = "/proc/net/psched";
     unsigned int a, b, c, d;
     FILE *stream;
 
+    if (!ovsthread_once_start(&once)) {
+        return;
+    }
+
     ticks_per_s = 1.0;
     buffer_hz = 100;
 
     stream = fopen(fn, "r");
     if (!stream) {
         VLOG_WARN("%s: open failed: %s", fn, ovs_strerror(errno));
-        return;
+        goto exit;
     }
 
     if (fscanf(stream, "%x %x %x %x", &a, &b, &c, &d) != 4) {
         VLOG_WARN("%s: read failed", fn);
         fclose(stream);
-        return;
+        goto exit;
     }
     VLOG_DBG("%s: psched parameters are: %u %u %u %u", fn, a, b, c, d);
     fclose(stream);
 
     if (!a || !c) {
         VLOG_WARN("%s: invalid scheduler parameters", fn);
-        return;
+        goto exit;
     }
 
     ticks_per_s = (double) a * c / b;
@@ -3811,6 +3818,9 @@ read_psched(void)
                   fn, a, b, c, d);
     }
     VLOG_DBG("%s: ticks_per_s=%f buffer_hz=%u", fn, ticks_per_s, buffer_hz);
+
+exit:
+    ovsthread_once_done(&once);
 }
 
 /* Returns the number of bytes that can be transmitted in 'ticks' ticks at a
@@ -3818,9 +3828,7 @@ read_psched(void)
 static unsigned int
 tc_ticks_to_bytes(unsigned int rate, unsigned int ticks)
 {
-    if (!buffer_hz) {
-        read_psched();
-    }
+    read_psched();
     return (rate * ticks) / ticks_per_s;
 }
 
@@ -3829,9 +3837,7 @@ tc_ticks_to_bytes(unsigned int rate, unsigned int ticks)
 static unsigned int
 tc_bytes_to_ticks(unsigned int rate, unsigned int size)
 {
-    if (!buffer_hz) {
-        read_psched();
-    }
+    read_psched();
     return rate ? ((unsigned long long int) ticks_per_s * size) / rate : 0;
 }
 
@@ -3840,9 +3846,7 @@ tc_bytes_to_ticks(unsigned int rate, unsigned int size)
 static unsigned int
 tc_buffer_per_jiffy(unsigned int rate)
 {
-    if (!buffer_hz) {
-        read_psched();
-    }
+    read_psched();
     return rate / buffer_hz;
 }
 
@@ -4556,9 +4560,10 @@ netdev_linux_get_ipv4(const struct netdev *netdev, struct in_addr *ip,
 static int
 af_packet_sock(void)
 {
-    static int sock = INT_MIN;
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+    static int sock;
 
-    if (sock == INT_MIN) {
+    if (ovsthread_once_start(&once)) {
         sock = socket(AF_PACKET, SOCK_RAW, 0);
         if (sock >= 0) {
             int error = set_nonblocking(sock);
@@ -4571,6 +4576,7 @@ af_packet_sock(void)
             VLOG_ERR("failed to create packet socket: %s",
                      ovs_strerror(errno));
         }
+        ovsthread_once_done(&once);
     }
 
     return sock;