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Re: [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is completed |
Date: |
Thu, 30 Jun 2016 05:22:43 -0400 (EDT) |
Hi
----- Original Message -----
> On Fri, Jun 24, 2016 at 03:51:09PM +0200, address@hidden wrote:
> > From: Marc-André Lureau <address@hidden>
> >
> > The chardev waits for an initial connection before starting qemu,
> > vhost-user wants the backend negotiation to be completed. vhost-user is
> > started in the net_vhost_user_event callback, which is synchronously
> > called after the socket is connected.
> >
> > Signed-off-by: Marc-André Lureau <address@hidden>
> > ---
> > net/vhost-user.c | 12 +++++++++++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > index 95ed2d2..4badd9e 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -24,6 +24,7 @@ typedef struct VhostUserState {
> > VHostNetState *vhost_net;
> > int watch;
> > uint64_t acked_features;
> > + bool started;
> > } VhostUserState;
> >
> > typedef struct VhostUserChardevProps {
> > @@ -211,6 +212,7 @@ static void net_vhost_user_event(void *opaque, int
> > event)
> > return;
> > }
> > qmp_set_link(name, true, &err);
> > + s->started = true;
> > break;
> > case CHR_EVENT_CLOSED:
> > qmp_set_link(name, false, &err);
> > @@ -248,7 +250,15 @@ static int net_vhost_user_init(NetClientState *peer,
> > const char *device,
> > s->chr = chr;
> > }
> >
> > - qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event,
> > nc[0].name);
> > + do {
> > + Error *err = NULL;
> > + if (qemu_chr_wait_connected(chr, &err) < 0) {
> > + error_report_err(err);
> > + return -1;
> > + }
> > + qemu_chr_add_handlers(chr, NULL, NULL,
> > + net_vhost_user_event, nc[0].name);
> > + } while (!s->started);
>
>
> I haven't looked at your patchset carefully yet, but I did a quick test,
> and showed that above code piece just breaks vhost-user: it's a dead loop
> that vhost-user net will be initiated again and again.
Interesting, thanks a lot for testing!
The vhost-user-test works just fine, as well as vhost-user-bridge.
> The dead loop is due to, we check "s->started" corresponding to last nc,
> while we set "s->started" corresponding to the first nc.
I see, that makes sense with multiqueue, I'll update the code. It would be
really nice to have a basic multiqueue test in vhost-user-test.
thanks
- [Qemu-devel] [PATCH v2 09/23] vhost: fix calling vhost_dev_cleanup() after vhost_dev_init(), (continued)
- [Qemu-devel] [PATCH v2 09/23] vhost: fix calling vhost_dev_cleanup() after vhost_dev_init(), marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 10/23] vhost: change some assert() for error_report() or silent fail, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 11/23] vhost: use error_report() instead of fprintf(stderr, ...), marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 12/23] vhost-user: check qemu_chr_fe_set_msgfds() return value, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 16/23] Revert "vhost-net: do not crash if backend is not present", marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 14/23] qemu-char: check socket is actually connected, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 18/23] vhost-net: success if backend has no ops->vhost_migration_done, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 17/23] get_vhost_net() should be != null after vhost_user_init, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is completed, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 20/23] char: add chr_wait_connected callback, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 19/23] vhost: add assert() to check runtime behaviour, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 13/23] vhost-user: check vhost_user_{read, write}() return value, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 21/23] char: add and use tcp_chr_wait_connected, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 23/23] tests: add /vhost-user/connect-fail test, marcandre . lureau, 2016/06/24