From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57396) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yl8aT-0007fU-Up for qemu-devel@nongnu.org; Thu, 23 Apr 2015 00:18:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yl8aO-0001a3-Ud for qemu-devel@nongnu.org; Thu, 23 Apr 2015 00:18:05 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:34463) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yl8aO-0001Zv-PC for qemu-devel@nongnu.org; Thu, 23 Apr 2015 00:18:00 -0400 Received: by pdbqa5 with SMTP id qa5so7334506pdb.1 for ; Wed, 22 Apr 2015 21:17:59 -0700 (PDT) Message-ID: <55387276.3070802@igel.co.jp> Date: Thu, 23 Apr 2015 13:17:58 +0900 From: Tetsuya Mukawa MIME-Version: 1.0 References: <1429598175-4793-1-git-send-email-mukawa@igel.co.jp> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] vhost-user: Add ability to know vhost-user backend disconnection List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nikolay Nikolaev Cc: VirtualOpenSystems Technical Team , qemu-devel On 2015/04/22 5:19, Nikolay Nikolaev wrote: > On Tue, Apr 21, 2015 at 9:36 AM, Tetsuya Mukawa wrote: >> Current QEMU cannot detect vhost-user backend disconnection. The >> patch adds ability to know it. >> To know disconnection, add watcher to detect G_IO_HUP event. When >> G_IO_HUP event is detected, the disconnected socket will be read >> to cause a CHR_EVENT_CLOSED. >> >> Signed-off-by: Tetsuya Mukawa >> --- >> net/vhost-user.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/net/vhost-user.c b/net/vhost-user.c >> index 1d86a2b..55c05a5 100644 >> --- a/net/vhost-user.c >> +++ b/net/vhost-user.c >> @@ -19,6 +19,7 @@ typedef struct VhostUserState { >> NetClientState nc; >> CharDriverState *chr; >> VHostNetState *vhost_net; >> + int watch; >> } VhostUserState; >> >> typedef struct VhostUserChardevProps { >> @@ -113,12 +114,23 @@ static void net_vhost_link_down(VhostUserState *s, bool link_down) >> } >> } >> >> +static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond, >> + void *opaque) >> +{ >> + VhostUserState *s = opaque; >> + uint8_t buf[1]; >> + >> + qemu_chr_fe_read_all(s->chr, buf, sizeof(buf)); > So you read the date from the buffer and just discard it? > Are you going to miss messages this way? > > Please clarify. Hi Nikolay, Thanks for comment. Yes, some messages might be lost, but it will be only happened after unix domain socket is closed by vhost-user backend. So I guess there is no side effect. Anyway, I just want to know vhost-user disconnection, so other ways are also nice. Do you have any suggestions about how to implement? Regards, Tetsuya > regards, > Nikolay Nikolaev > >> + return FALSE; >> +} >> + >> static void net_vhost_user_event(void *opaque, int event) >> { >> VhostUserState *s = opaque; >> >> switch (event) { >> case CHR_EVENT_OPENED: >> + s->watch = qemu_chr_fe_add_watch(s->chr, G_IO_HUP, net_vhost_user_watch, s); >> vhost_user_start(s); >> net_vhost_link_down(s, false); >> error_report("chardev \"%s\" went up", s->chr->label); >> @@ -126,6 +138,8 @@ static void net_vhost_user_event(void *opaque, int event) >> case CHR_EVENT_CLOSED: >> net_vhost_link_down(s, true); >> vhost_user_stop(s); >> + g_source_remove(s->watch); >> + s->watch = 0; >> error_report("chardev \"%s\" went down", s->chr->label); >> break; >> } >> -- >> 1.9.1 >> >>