Avoiding a lengthy lock on the Channels list when starting a recording

3 files changed, 17 insertions, 2 deletions

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index c6efd469..1c1602f8 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -3639,6 +3639,7 @@ Helmut Binder <cco@aon.at>
  for fixing a bug in handling shared PMTs, where after the first pass not all SIDs of a
  PMT pid were checked any more
  for reporting a problem with PMT handling in case locking the Channels list times out
+ for avoiding a lengthy lock on the Channels list when starting a recording
 
 Ulrich Eckhardt <uli@uli-eckhardt.de>
  for reporting a problem with shutdown after user inactivity in case a plugin is
diff --git a/HISTORY b/HISTORY
index b1167360..b0467e9e 100644
--- a/HISTORY
+++ b/HISTORY
@@ -9553,3 +9553,5 @@ Video Disk Recorder Revision History
   PMT pid were checked any more (thanks to Helmut Binder).
 - Fixed PMT handling in case locking the Channels list times out (reported by Helmut
   Binder).
+- Avoiding a lengthy lock on the Channels list when starting a recording (thanks to
+  Helmut Binder).
diff --git a/menu.c b/menu.c
index 1a295dc7..724c0a22 100644
--- a/menu.c
+++ b/menu.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: menu.c 4.87 2020/11/06 13:13:05 kls Exp $
+ * $Id: menu.c 4.88 2020/12/12 22:01:01 kls Exp $
  */
 
 #include "menu.h"
@@ -5229,6 +5229,11 @@ cRecordControl::cRecordControl(cDevice *Device, cTimers *Timers, cTimer *Timer,
   const char *LastReplayed = cReplayControl::LastReplayed(); // must do this before locking schedules!
   // Whatever happens here, the timers will be modified in some way...
   Timers->SetModified();
+  cStateKey ChannelsStateKey;
+  // To create a new timer, we need to make shure there is
+  // a lock on Channels prior to the Schedules locking below
+  if (!Timer)
+     cChannels::GetChannelsRead(ChannelsStateKey);
   // We're going to work with an event here, so we need to prevent
   // others from modifying any EPG data:
   cStateKey SchedulesStateKey;
@@ -5244,6 +5249,7 @@ cRecordControl::cRecordControl(cDevice *Device, cTimers *Timers, cTimer *Timer,
      timer = new cTimer(true, Pause);
      Timers->Add(timer);
      instantId = cString::sprintf(cDevice::NumDevices() > 1 ? "%s - %d" : "%s", timer->Channel()->Name(), device->DeviceNumber() + 1);
+     ChannelsStateKey.Remove();
      }
   timer->SetPending(true);
   timer->SetRecording(true);
@@ -5380,7 +5386,8 @@ bool cRecordControls::Start(cTimers *Timers, cTimer *Timer, bool Pause)
   LastNoDiskSpaceMessage = 0;
 
   ChangeState();
-  LOCK_CHANNELS_READ;
+  cStateKey StateKey;
+  const cChannels *Channels = cChannels::GetChannelsRead(StateKey);
   int ch = Timer ? Timer->Channel()->Number() : cDevice::CurrentChannel();
   if (const cChannel *Channel = Channels->GetByNumber(ch)) {
      int Priority = Timer ? Timer->Priority() : Pause ? Setup.PausePriority : Setup.DefaultPriority;
@@ -5388,9 +5395,12 @@ bool cRecordControls::Start(cTimers *Timers, cTimer *Timer, bool Pause)
      if (device) {
         dsyslog("switching device %d to channel %d %s (%s)", device->DeviceNumber() + 1, Channel->Number(), *Channel->GetChannelID().ToString(), Channel->Name());
         if (!device->SwitchChannel(Channel, false)) {
+           StateKey.Remove();
            ShutdownHandler.RequestEmergencyExit();
            return false;
            }
+        StateKey.Remove();
+        Channels = NULL;
         if (!Timer || Timer->Matches()) {
            for (int i = 0; i < MAXRECORDCONTROLS; i++) {
                if (!RecordControls[i]) {
@@ -5407,6 +5417,8 @@ bool cRecordControls::Start(cTimers *Timers, cTimer *Timer, bool Pause)
      }
   else
      esyslog("ERROR: channel %d not defined!", ch);
+  if (Channels)
+     StateKey.Remove();
   return false;
 }