use folly::synchronized for I2cControllerStats

Summary: We were running into race conditions with these stats, make the I2cControllerStats object synchronized

Reviewed By: harshitgulati18

Differential Revision: D64145306

fbshipit-source-id: 1615c2ef25f93446ad5018b1aee3f48b2ce88bf3

fboss/lib/i2c/BUCK

@@ -45,6 +45,7 @@ cpp_library(
         "//fboss/agent:utils",
         "//folly:format",
         "//folly:range",
+        "//folly:synchronized",
         "//folly/io/async:async_base",
         "//folly/lang:bits",
         "//folly/logging:logging",

fboss/lib/i2c/I2cController.h

@@ -9,6 +9,7 @@
  */
 #pragma once
 
+#include <folly/Synchronized.h>
 #include <stdint.h>
 #include "fboss/lib/i2c/gen-cpp2/i2c_controller_stats_types.h"
 
@@ -18,50 +19,51 @@ namespace facebook::fboss {
  */
 class I2cController {
  public:
-  I2cController(std::string name) {
-    *i2cControllerPlatformStats_.controllerName_() = name;
+  explicit I2cController(std::string name) {
+    *i2cControllerPlatformStats_.wlock()->controllerName_() = name;
   }
   virtual ~I2cController() {}
 
   // Reset all i2c stats
   void resetStats() {
-    *i2cControllerPlatformStats_.readTotal_() = 0;
-    *i2cControllerPlatformStats_.readFailed_() = 0;
-    *i2cControllerPlatformStats_.readBytes_() = 0;
-    *i2cControllerPlatformStats_.writeTotal_() = 0;
-    *i2cControllerPlatformStats_.writeFailed_() = 0;
-    *i2cControllerPlatformStats_.writeBytes_() = 0;
+    auto stats = i2cControllerPlatformStats_.wlock();
+    *stats->readTotal_() = 0;
+    *stats->readFailed_() = 0;
+    *stats->readBytes_() = 0;
+    *stats->writeTotal_() = 0;
+    *stats->writeFailed_() = 0;
+    *stats->writeBytes_() = 0;
   }
   // Total number of reads
   void incrReadTotal(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.readTotal_() += count;
+    *i2cControllerPlatformStats_.wlock()->readTotal_() += count;
   }
   // Total Read failures
   void incrReadFailed(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.readFailed_() += count;
+    *i2cControllerPlatformStats_.wlock()->readFailed_() += count;
   }
   // Number of bytes read
   void incrReadBytes(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.readBytes_() += count;
+    *i2cControllerPlatformStats_.wlock()->readBytes_() += count;
   }
   // Total number of writes
   void incrWriteTotal(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.writeTotal_() += count;
+    *i2cControllerPlatformStats_.wlock()->writeTotal_() += count;
   }
   // Total write failures
   void incrWriteFailed(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.writeFailed_() += count;
+    *i2cControllerPlatformStats_.wlock()->writeFailed_() += count;
   }
   // Number of bytes written
   void incrWriteBytes(uint32_t count = 1) {
-    *i2cControllerPlatformStats_.writeBytes_() += count;
+    *i2cControllerPlatformStats_.wlock()->writeBytes_() += count;
   }
 
   /* Get the I2c transaction stats from the i2c controller
    */
   const I2cControllerStats getI2cControllerPlatformStats() const {
     // return the structre reference of latest i2c transaction stats
-    return i2cControllerPlatformStats_;
+    return *i2cControllerPlatformStats_.rlock();
   }
 
   virtual void i2cTimeProfilingStart() {}
@@ -72,7 +74,7 @@ class I2cController {
 
  private:
   // Platform i2c controller stats
-  I2cControllerStats i2cControllerPlatformStats_;
+  folly::Synchronized<I2cControllerStats> i2cControllerPlatformStats_;
 };
 
 } // namespace facebook::fboss