[ovs-dev] [PATCH v2 1/5] rstp: Init a recursive mutex for rstp.

[nickcooper-zhangtonghao]

* This patch will be used for next patch. The 'rstp/show' command,
which uses the mutex, calls functions which also use the mutex.
We should init it as a recursive mutex.

* Some rstp tests of OvS, which run with ovstest, does not run rstp_init
in the bridge_init. We should call rstp_init when creating the rstp
and stp also do that, otherwise tests fail.

* This patch remove the rstp_mutex in header file and make it static
in c file because we only use it in lib/rstp.c

Signed-off-by: nickcooper-zhangtonghao <nic at opencloud.tech>
---
 lib/rstp.c | 15 ++++++++++++---
 lib/rstp.h |  6 ------
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/lib/rstp.c b/lib/rstp.c
index 907a907..6f1c1e3 100644
--- a/lib/rstp.c
+++ b/lib/rstp.c
@@ -50,7 +50,7 @@
 
 VLOG_DEFINE_THIS_MODULE(rstp);
 
-struct ovs_mutex rstp_mutex = OVS_MUTEX_INITIALIZER;
+static struct ovs_mutex rstp_mutex;
 
 static struct ovs_list all_rstps__ = OVS_LIST_INITIALIZER(&all_rstps__);
 static struct ovs_list *const all_rstps OVS_GUARDED_BY(rstp_mutex) = &all_rstps__;
@@ -239,8 +239,15 @@ void
 rstp_init(void)
     OVS_EXCLUDED(rstp_mutex)
 {
-    unixctl_command_register("rstp/tcn", "[bridge]", 0, 1, rstp_unixctl_tcn,
-                             NULL);
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+
+    if (ovsthread_once_start(&once)) {
+        ovs_mutex_init_recursive(&rstp_mutex);
+
+        unixctl_command_register("rstp/tcn", "[bridge]", 0, 1, rstp_unixctl_tcn,
+                                 NULL);
+        ovsthread_once_done(&once);
+    }
 }
 
 /* Creates and returns a new RSTP instance that initially has no ports. */
@@ -255,6 +262,8 @@ rstp_create(const char *name, rstp_identifier bridge_address,
 
     VLOG_DBG("Creating RSTP instance");
 
+    rstp_init();
+
     rstp = xzalloc(sizeof *rstp);
     rstp->name = xstrdup(name);
 
diff --git a/lib/rstp.h b/lib/rstp.h
index 4942d59..78e07fb 100644
--- a/lib/rstp.h
+++ b/lib/rstp.h
@@ -36,12 +36,6 @@
 #include "compiler.h"
 #include "util.h"
 
-/* Thread Safety: Callers passing in RSTP and RSTP port object
- * pointers must hold a reference to the passed object to ensure that
- * the object does not become stale while it is being accessed. */
-
-extern struct ovs_mutex rstp_mutex;
-
 #define RSTP_MAX_PORTS 4095
 
 struct dp_packet;
-- 
1.8.3.1