[libvirt] [PATCH] Revert "rpc: Discard non-blocking calls only when necessary"

[Jiri Denemark]

This reverts commit b1e374a7ac56927cfe62435179bf0bba1e08b372, which was
rather bad since I failed to consider all sides of the issue. Thus, the
reverted patch actually breaks more than what it fixes and clients
(which may even be libvirtd during p2p migrations) will likely end up
with a corrupted dispatch queue.
---

I will send proper replacement for the reverted patch later once I'm convinced
it's correct (more than I was convinced the original one was correct) :-P

 src/rpc/virnetclient.c |   21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
index 3a60db6..d88288d 100644
--- a/src/rpc/virnetclient.c
+++ b/src/rpc/virnetclient.c
@@ -1265,13 +1265,6 @@ static void virNetClientIOEventLoopPassTheBuck(virNetClientPtr client, virNetCli
     }
     client->haveTheBuck = false;
 
-    /* Remove non-blocking calls from the dispatch list since there is no
-     * call with a thread in the list which could take care of them.
-     */
-    virNetClientCallRemovePredicate(&client->waitDispatch,
-                                    virNetClientIOEventLoopRemoveNonBlocking,
-                                    thiscall);
-
     VIR_DEBUG("No thread to pass the buck to");
     if (client->wantClose) {
         virNetClientCloseLocked(client);
@@ -1315,9 +1308,12 @@ static int virNetClientIOEventLoop(virNetClientPtr client,
         if (virNetSocketHasCachedData(client->sock) || client->wantClose)
             timeout = 0;
 
-        /* If we are non-blocking, we don't want to sleep in poll()
+        /* If there are any non-blocking calls in the queue,
+         * then we don't want to sleep in poll()
          */
-        if (thiscall->nonBlock)
+        if (virNetClientCallMatchPredicate(client->waitDispatch,
+                                           virNetClientIOEventLoopWantNonBlock,
+                                           NULL))
             timeout = 0;
 
         fds[0].events = fds[0].revents = 0;
@@ -1422,6 +1418,13 @@ static int virNetClientIOEventLoop(virNetClientPtr client,
                                         virNetClientIOEventLoopRemoveDone,
                                         thiscall);
 
+        /* Iterate through waiting calls and if any are
+         * non-blocking, remove them from the dispatch list...
+         */
+        virNetClientCallRemovePredicate(&client->waitDispatch,
+                                        virNetClientIOEventLoopRemoveNonBlocking,
+                                        thiscall);
+
         /* Now see if *we* are done */
         if (thiscall->mode == VIR_NET_CLIENT_MODE_COMPLETE) {
             virNetClientCallRemove(&client->waitDispatch, thiscall);
-- 
1.7.10.2