Hi Marc-André,
[very old patch...]
On 27/2/17 11:49, Marc-André Lureau wrote:
Since commit b0a335e351103bf92f3f9d0bd5759311be8156ac, a socket write
may trigger a disconnect events, calling vhost_user_stop() and clearing
all the vhost_dev strutures holding data that vhost.c functions expect
to remain valid. Delay the cleanup to keep the vhost_dev structure
valid during the vhost.c functions.
Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
v3:
- use aio_bh_schedule_oneshot(), as suggest by Paolo
v2:
- fix reconnect race
net/vhost-user.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 46 insertions(+), 7 deletions(-)
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 77b8110f8c..e7e63408a1 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -190,7 +190,35 @@ static gboolean net_vhost_user_watch(GIOChannel *chan,
GIOCondition cond,
qemu_chr_fe_disconnect(&s->chr);
- return FALSE;
+ return TRUE;
Do you mind explaining this change again, it is not clear from
the commit description. We listen to G_IO_HUP, got a SIGHUP so
we disconnect the chardev but keep listening for future HUP?
In which case can that happen? How can we get a chardev connected
and initialized here without calling net_init_vhost_user() again?
+}
+
+static void net_vhost_user_event(void *opaque, int event);
+
+static void chr_closed_bh(void *opaque)
+{
+ const char *name = opaque;
+ NetClientState *ncs[MAX_QUEUE_NUM];
+ VhostUserState *s;
+ Error *err = NULL;
+ int queues;
+
+ queues = qemu_find_net_clients_except(name, ncs,
+ NET_CLIENT_DRIVER_NIC,
+ MAX_QUEUE_NUM);
+ assert(queues < MAX_QUEUE_NUM);
+
+ s = DO_UPCAST(VhostUserState, nc, ncs[0]);
+
+ qmp_set_link(name, false, &err);
+ vhost_user_stop(queues, ncs);
+
+ qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
+ opaque, NULL, true);
+
+ if (err) {
+ error_report_err(err);
+ }
}
static void net_vhost_user_event(void *opaque, int event)
@@ -212,20 +240,31 @@ static void net_vhost_user_event(void *opaque, int event)
trace_vhost_user_event(chr->label, event);
switch (event) {
case CHR_EVENT_OPENED:
- s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
- net_vhost_user_watch, s);
if (vhost_user_start(queues, ncs, &s->chr) < 0) {
qemu_chr_fe_disconnect(&s->chr);
return;
}
+ s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
+ net_vhost_user_watch, s);
qmp_set_link(name, true, &err);
s->started = true;
break;
case CHR_EVENT_CLOSED:
- qmp_set_link(name, false, &err);
- vhost_user_stop(queues, ncs);
- g_source_remove(s->watch);
- s->watch = 0;
+ /* a close event may happen during a read/write, but vhost
+ * code assumes the vhost_dev remains setup, so delay the
+ * stop & clear to idle.
+ * FIXME: better handle failure in vhost code, remove bh
+ */
+ if (s->watch) {
+ AioContext *ctx = qemu_get_current_aio_context();
+
+ g_source_remove(s->watch);
+ s->watch = 0;
+ qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL,
+ NULL, NULL, false);
+
+ aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
+ }
break;
}
