selectabletimer: add mutex to start() and stop()

common/selectabletimer.cpp

@@ -21,6 +21,7 @@ SelectableTimer::SelectableTimer(const timespec& interval, int pri)
         SWSS_LOG_THROW("failed to create timerfd, errno: %s", strerror(errno));
     }
     setInterval(interval);
+    m_alive = false;
 }
 
 SelectableTimer::~SelectableTimer()
@@ -36,22 +37,40 @@ SelectableTimer::~SelectableTimer()
 
 void SelectableTimer::start()
 {
-    // Set the timer interval and the timer is automatically started
-    int rc = timerfd_settime(m_tfd, 0, &m_interval, NULL);
-    if (rc == -1)
+    m_mutex.lock();
+    if (!m_alive)
     {
-        SWSS_LOG_THROW("failed to set timerfd, errno: %s", strerror(errno));
+        // Set the timer interval and the timer is automatically started
+        int rc = timerfd_settime(m_tfd, 0, &m_interval, NULL);
+        if (rc == -1)
+        {
+            SWSS_LOG_THROW("failed to set timerfd, errno: %s", strerror(errno));
+        }
+        else
+        {
+            m_alive = true;
+        }
     }
+    m_mutex.unlock();
 }
 
 void SelectableTimer::stop()
 {
-    // Set the timer interval and the timer is automatically started
-    int rc = timerfd_settime(m_tfd, 0, &m_zero, NULL);
-    if (rc == -1)
+    m_mutex.lock();
+    if (m_alive)
     {
-        SWSS_LOG_THROW("failed to set timerfd to zero, errno: %s", strerror(errno));
+        // Set the timer interval and the timer is automatically started
+        int rc = timerfd_settime(m_tfd, 0, &m_zero, NULL);
+        if (rc == -1)
+        {
+            SWSS_LOG_THROW("failed to set timerfd to zero, errno: %s", strerror(errno));
+        }
+        else
+        {
+            m_alive = false;
+        }
     }
+    m_mutex.unlock();
 }
 
 void SelectableTimer::reset()

common/selectabletimer.h

@@ -3,6 +3,7 @@
 #include <string>
 #include <vector>
 #include <limits>
+#include <mutex>
 #include <sys/timerfd.h>
 #include "selectable.h"
 
@@ -22,6 +23,8 @@ class SelectableTimer : public Selectable
     uint64_t readData() override;
 
 private:
+    std::mutex m_mutex;
+    bool m_alive;
     int m_tfd;
     itimerspec m_interval;
     itimerspec m_zero;