From fa59ccb89d06755b6ed1200debe6046417c8daf6 Mon Sep 17 00:00:00 2001
From: Pavel Emelyanov <xemul@scylladb.com>
Date: Thu, 7 Apr 2022 19:53:01 +0300
Subject: [PATCH] snitch: Declare snitch_ptr peering and rework container()
 method

This patch makes the snitch base class reference local snitch_ptr, not
its sharded<> container and, respectively, makes the base container()
method return _backreference->container() instead.

The motivation of this change is, again, in the next patch, which will
move snitch_ptr<->driver_object linkage into snitch_ptr constructor.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
---
 locator/production_snitch_base.cc |  4 ++--
 locator/production_snitch_base.hh |  8 ++++----
 locator/snitch_base.hh            | 10 +++++-----
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/locator/production_snitch_base.cc b/locator/production_snitch_base.cc
index 5644fb922a..9f852622f3 100644
--- a/locator/production_snitch_base.cc
+++ b/locator/production_snitch_base.cc
@@ -58,8 +58,8 @@ sstring production_snitch_base::get_datacenter(inet_address endpoint) {
                              default_dc);
 }
 
-void production_snitch_base::set_my_distributed(distributed<snitch_ptr>* d) {
-    _my_distributed = d;
+void production_snitch_base::set_backreference(snitch_ptr& d) {
+    _backreference = &d;
 }
 
 void production_snitch_base::reset_io_state() {
diff --git a/locator/production_snitch_base.hh b/locator/production_snitch_base.hh
index 707730b4bf..8d7c398a89 100644
--- a/locator/production_snitch_base.hh
+++ b/locator/production_snitch_base.hh
@@ -44,7 +44,7 @@ public:
 
     virtual sstring get_rack(inet_address endpoint) override;
     virtual sstring get_datacenter(inet_address endpoint) override;
-    virtual void set_my_distributed(distributed<snitch_ptr>* d) override;
+    virtual void set_backreference(snitch_ptr& d) override;
 
     void reset_io_state();
 
@@ -81,12 +81,12 @@ protected:
     std::unordered_map<sstring, sstring> _prop_values;
 
     sharded<snitch_ptr>& container() noexcept {
-        assert(_my_distributed != nullptr);
-        return *_my_distributed;
+        assert(_backreference != nullptr);
+        return _backreference->container();
     }
 
 private:
     size_t _prop_file_size;
-    distributed<snitch_ptr>* _my_distributed = nullptr;
+    snitch_ptr* _backreference = nullptr;
 };
 } // namespace locator
diff --git a/locator/snitch_base.hh b/locator/snitch_base.hh
index 7161fba839..9cbfa703b1 100644
--- a/locator/snitch_base.hh
+++ b/locator/snitch_base.hh
@@ -155,7 +155,7 @@ public:
     virtual sstring get_name() const = 0;
 
     // should be called for production snitches before calling start()
-    virtual void set_my_distributed(distributed<snitch_ptr>* d)  {
+    virtual void set_backreference(snitch_ptr& d)  {
         //noop by default
     }
 
@@ -191,7 +191,7 @@ protected:
     } _state = snitch_state::initializing;
 };
 
-struct snitch_ptr {
+struct snitch_ptr : public peering_sharded_service<snitch_ptr> {
     using ptr_type = i_endpoint_snitch::ptr_type;
     future<> stop() {
         if (_ptr) {
@@ -253,13 +253,13 @@ future<> i_endpoint_snitch::init_snitch_obj(
         [&snitch_obj, snitch_name = std::move(snitch_name), a = std::make_tuple(std::forward<A>(a)...)] () {
         // ...then, create the snitches...
         return snitch_obj.invoke_on_all(
-            [snitch_name, a, &snitch_obj] (snitch_ptr& local_inst) {
+            [snitch_name, a] (snitch_ptr& local_inst) {
             try {
                 auto s(std::move(apply([snitch_name] (A&&... a) {
                     return create_object<i_endpoint_snitch>(snitch_name, std::forward<A>(a)...);
                 }, std::move(a))));
 
-                s->set_my_distributed(&snitch_obj);
+                s->set_backreference(local_inst);
                 local_inst = std::move(s);
             } catch (no_such_class& e) {
                 logger().error("Can't create snitch {}: not supported", snitch_name);
@@ -370,7 +370,7 @@ future<> i_endpoint_snitch::reset_snitch(
         // per-shard level (since users are holding snitch_ptr objects only)
         //
         tmp_snitch.invoke_on_all([] (snitch_ptr& local_inst) {
-            local_inst->set_my_distributed(&snitch_instance());
+            local_inst->set_backreference(snitch_instance().local());
             snitch_instance().local() = std::move(local_inst);
 
             return make_ready_future<>();