Use run_in_background in preference to preserve_fn

While I was going through uses of preserve_fn for other PRs, I converted places
which only use the wrapped function once to use run_in_background, to avoid
creating the function object.

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py

index d59adc236e..c2edf87e58 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -341,7 +341,7 @@ def make_deferred_yieldable(deferred):
     returning a deferred. Then, when the deferred completes, restores the
     current logcontext before running callbacks/errbacks.
 
-    (This is more-or-less the opposite operation to preserve_fn.)
+    (This is more-or-less the opposite operation to run_in_background.)
     """
     if isinstance(deferred, defer.Deferred) and not deferred.called:
         prev_context = LoggingContext.set_current_context(LoggingContext.sentinel)