char: Fix removing wrong GSource that be found by fd_in_tag

We use fd_in_tag to find a GSource, fd_in_tag is return value of
g_source_attach(GSource *source, GMainContext *context), the return
value is unique only in the same context, so we may get the same
values with different 'context' parameters.

It is no problem to find the right fd_in_tag by using
 g_main_context_find_source_by_id(GMainContext *context, guint source_id)
while there is only one default main context.

But colo-compare tries to create/use its own context, and if we pass wrong
'context' parameter with right fd_in_tag, we will find a wrong GSource to handle.
We tried to fix the related codes in commit b43decb015a6efeb9e3cdbdb80f6547ad7248a4c,
but it didn't fix the bug completely, because we still have some codes didn't pass
*right* context parameter for remove_fd_in_watch().

Let's fix it by record the GSource directly instead of fd_in_tag.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1492564532-91680-1-git-send-email-zhang.zhanghailiang@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/chardev/char-udp.c b/chardev/char-udp.c
index 804bd22efa..12240e528a 100644
--- a/chardev/char-udp.c
+++ b/chardev/char-udp.c
@@ -81,7 +81,7 @@ static gboolean udp_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
     ret = qio_channel_read(
         s->ioc, (char *)s->buf, sizeof(s->buf), NULL);
     if (ret <= 0) {
-        remove_fd_in_watch(chr, NULL);
+        remove_fd_in_watch(chr);
         return FALSE;
     }
     s->bufcnt = ret;
@@ -101,9 +101,9 @@ static void udp_chr_update_read_handler(Chardev *chr,
 {
     UdpChardev *s = UDP_CHARDEV(chr);
 
-    remove_fd_in_watch(chr, NULL);
+    remove_fd_in_watch(chr);
     if (s->ioc) {
-        chr->fd_in_tag = io_add_watch_poll(chr, s->ioc,
+        chr->gsource = io_add_watch_poll(chr, s->ioc,
                                            udp_chr_read_poll,
                                            udp_chr_read, chr,
                                            context);
@@ -115,7 +115,7 @@ static void char_udp_finalize(Object *obj)
     Chardev *chr = CHARDEV(obj);
     UdpChardev *s = UDP_CHARDEV(obj);
 
-    remove_fd_in_watch(chr, NULL);
+    remove_fd_in_watch(chr);
     if (s->ioc) {
         object_unref(OBJECT(s->ioc));
     }