[PATCH 1/9] monitor: Honor QMP request for fd removal immediately

[Fabiano Rosas]

We're enabling using the fdset interface to pass file descriptors for
use in the migration code. Since migrations can happen more than once
during the VMs lifetime, we need a way to remove an fd from the fdset
at the end of migration.

The current code only removes an fd from the fdset if the VM is
running. This causes a QMP call to "remove-fd" to not actually remove
the fd if the VM happens to be stopped.

While the fd would eventually be removed when monitor_fdset_cleanup()
is called again, the user request should be honored and the fd
actually removed. Calling remove-fd + query-fdset shows a recently
removed fd still present.

The runstate_is_running() check was introduced by commit ebe52b592d
("monitor: Prevent removing fd from set during init"), which by the
shortlog indicates that they were trying to avoid removing an
yet-unduplicated fd too early.

I don't see why an fd explicitly removed with qmp_remove_fd() should
be under runstate_is_running(). I'm assuming this was a mistake when
adding the parenthesis around the expression.

Move the runstate_is_running() check to apply only to the
QLIST_EMPTY(dup_fds) side of the expression and ignore it when
mon_fdset_fd->removed has been explicitly set.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 monitor/fds.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/monitor/fds.c b/monitor/fds.c
index d86c2c674c..4ec3b7eea9 100644
--- a/monitor/fds.c
+++ b/monitor/fds.c
@@ -173,9 +173,9 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
     MonFdsetFd *mon_fdset_fd_next;
 
     QLIST_FOREACH_SAFE(mon_fdset_fd, &mon_fdset->fds, next, mon_fdset_fd_next) 
{
-        if ((mon_fdset_fd->removed ||
-                (QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0)) &&
-                runstate_is_running()) {
+        if (mon_fdset_fd->removed ||
+            (QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0 &&
+             runstate_is_running())) {
             close(mon_fdset_fd->fd);
             g_free(mon_fdset_fd->opaque);
             QLIST_REMOVE(mon_fdset_fd, next);
-- 
2.35.3