reactor: Generalize timer removal

All three reactor::del_timer() implementations use the same logic that
fits naturally to timer_set itself. The original remove() method is kept
as memcached needs one, since it doesn't mess with expired lists.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

include/seastar/core/timer-set.hh

@@ -160,6 +160,19 @@ public:
         }
     }
 
+    /**
+     * Removes timer from the active set or the expired list, if the timer is expired
+     */
+    void remove(Timer& timer, timer_list_t& expired) noexcept
+    {
+        if (timer._expired) {
+            expired.erase(expired.iterator_to(timer));
+            timer._expired = false;
+        } else {
+            remove(timer);
+        }
+    }
+
     /**
      * Expires active timers.
      *

src/core/reactor.cc

@@ -2463,12 +2463,7 @@ bool reactor::queue_timer(timer<steady_clock_type>* tmr) noexcept {
 }
 
 void reactor::del_timer(timer<steady_clock_type>* tmr) noexcept {
-    if (tmr->_expired) {
-        _expired_timers.erase(_expired_timers.iterator_to(*tmr));
-        tmr->_expired = false;
-    } else {
-        _timers.remove(*tmr);
-    }
+    _timers.remove(*tmr, _expired_timers);
 }
 
 void reactor::add_timer(timer<lowres_clock>* tmr) noexcept {
@@ -2482,12 +2477,7 @@ bool reactor::queue_timer(timer<lowres_clock>* tmr) noexcept {
 }
 
 void reactor::del_timer(timer<lowres_clock>* tmr) noexcept {
-    if (tmr->_expired) {
-        _expired_lowres_timers.erase(_expired_lowres_timers.iterator_to(*tmr));
-        tmr->_expired = false;
-    } else {
-        _lowres_timers.remove(*tmr);
-    }
+    _lowres_timers.remove(*tmr, _expired_lowres_timers);
 }
 
 void reactor::add_timer(timer<manual_clock>* tmr) noexcept {
@@ -2499,12 +2489,7 @@ bool reactor::queue_timer(timer<manual_clock>* tmr) noexcept {
 }
 
 void reactor::del_timer(timer<manual_clock>* tmr) noexcept {
-    if (tmr->_expired) {
-        _expired_manual_timers.erase(_expired_manual_timers.iterator_to(*tmr));
-        tmr->_expired = false;
-    } else {
-        _manual_timers.remove(*tmr);
-    }
+    _manual_timers.remove(*tmr, _expired_manual_timers);
 }
 
 void reactor::at_exit(noncopyable_function<future<> ()> func) {