char: change qemu_chr_fe_add_watch to return unsigned

g_source_attach can return any value between 1 and UINT_MAX if you let
QEMU run long enough.  However, qemu_chr_fe_add_watch can also return
a negative errno value when the device is disconnected or does not
support chr_add_watch.  Change it to return zero to avoid overloading
these values.

Fix the cadence_uart which asserts in this case (easily obtained with
"-serial pty").

Tested-by: Bret Ketchum <bcketchum@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/vhost-user.c b/net/vhost-user.c
index d72ce9b490..636899a877 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -22,7 +22,7 @@ typedef struct VhostUserState {
     NetClientState nc;
     CharDriverState *chr;
     VHostNetState *vhost_net;
-    int watch;
+    guint watch;
     uint64_t acked_features;
 } VhostUserState;