Hi On Wed, Jul 5, 2023 at 2:02 PM Philippe Mathieu-Daudé <[email protected]> wrote:
> 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 <[email protected]> > > --- > > 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? > I think the point was simply to keep the source ID valid, until the cleanup happens and calls g_source_remove(). Is there any issue with that? we can probably set s->watch = 0 in the source callback instead and check the watch before removing it. > > +} > > + > > +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; > > } > > > > -- Marc-André Lureau
