[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] vhost-user: delay vhost_user_stop
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH] vhost-user: delay vhost_user_stop |
Date: |
Mon, 27 Feb 2017 05:16:51 -0500 (EST) |
Hi
----- Original Message -----
> * Marc-André Lureau (address@hidden) 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 <address@hidden>
>
> This does get me through a 'make check' succesfully.
>
Yes, it's not optimal, but there is so much cleanup to deal with otherwise,
than I am inclined to go with this approach for now, and keep the FIXME for 2.10
I'll update the patch to avoid the race on reconnect.
> Dave
>
> > ---
> > net/vhost-user.c | 49 +++++++++++++++++++++++++++++++++++++++++++------
> > 1 file changed, 43 insertions(+), 6 deletions(-)
> >
> > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > index 77b8110f8c..00573c8ac8 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -25,6 +25,7 @@ typedef struct VhostUserState {
> > guint watch;
> > uint64_t acked_features;
> > bool started;
> > + QEMUBH *chr_closed_bh;
> > } VhostUserState;
> >
> > VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
> > @@ -190,9 +191,40 @@ static gboolean net_vhost_user_watch(GIOChannel *chan,
> > GIOCondition cond,
> >
> > qemu_chr_fe_disconnect(&s->chr);
> >
> > + s->watch = 0;
> > return FALSE;
> > }
> >
> > +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);
> > + if (s->watch) {
> > + g_source_remove(s->watch);
> > + }
> > + s->watch = 0;
> > +
> > + qemu_bh_delete(s->chr_closed_bh);
> > + s->chr_closed_bh = NULL;
> > +
> > + if (err) {
> > + error_report_err(err);
> > + }
> > +}
> > +
> > static void net_vhost_user_event(void *opaque, int event)
> > {
> > const char *name = opaque;
> > @@ -212,20 +244,25 @@ 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->chr_closed_bh = qemu_bh_new(chr_closed_bh, opaque);
> > 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->chr_closed_bh) {
> > + qemu_bh_schedule(s->chr_closed_bh);
> > + }
> > break;
> > }
> >
> > --
> > 2.12.0.rc2.3.gc93709801
> >
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>