From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35189) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZa7q-0006jp-6d for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:30:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZa7m-0002OM-82 for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:30:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34648) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eZa7l-0002M4-Vb for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:30:18 -0500 References: <1515516013-16604-1-git-send-email-jianjay.zhou@huawei.com> <48f2d18b-b58c-dd08-29ff-34b5f8c2d780@redhat.com> From: Jason Wang Message-ID: Date: Thu, 11 Jan 2018 18:30:05 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v5 2/4][RFC] tap: do not close fd if only vhost failed to initialize List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Zhoujian (jay)" , "qemu-devel@nongnu.org" Cc: "Huangweidong (C)" , "mst@redhat.com" , "wangxin (U)" , "Gonglei (Arei)" , "imammedo@redhat.com" , "Liuzhe (Ahriy, Euler)" On 2018=E5=B9=B401=E6=9C=8811=E6=97=A5 11:54, Zhoujian (jay) wrote: > Hi Jason, > >> -----Original Message----- >> From: Jason Wang [mailto:jasowang@redhat.com] >> Sent: Thursday, January 11, 2018 11:35 AM >> To: Zhoujian (jay) ; qemu-devel@nongnu.org >> Cc: Huangweidong (C) ; mst@redhat.com; wangx= in (U) >> ; Gonglei (Arei) = ; >> imammedo@redhat.com; Liuzhe (Ahriy, Euler) >> Subject: Re: [Qemu-devel] [PATCH v5 2/4][RFC] tap: do not close fd if = only >> vhost failed to initialize >> >> >> >> On 2018=E5=B9=B401=E6=9C=8810=E6=97=A5 15:39, Zhoujian (jay) wrote: >>>>>> + *vhost_init_failed =3D true; >>>> Why not simply check s->vhost_net after call net_init_tap_one()? >>> s->vhost_net is always NULL if net_init_tap_one() failed, it can't >> distinguish >>> failure reasons. >> On which condition net_init_tap_one() fail but s->vhost_net is set? > No, it does not exist, so we could not use s->vhost_net to decide > whether close the fd of tap when error occurred. > > > Maybe the patch below will be much better to understand, please have a = look. > > diff --git a/net/tap.c b/net/tap.c > index 979e622..a5c5111 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -642,7 +642,8 @@ static void net_init_tap_one(const NetdevTapOptions= *tap, NetClientState *peer, > const char *model, const char *name, > const char *ifname, const char *script, > const char *downscript, const char *vhos= tfdname, > - int vnet_hdr, int fd, Error **errp) > + int vnet_hdr, int fd, Error **errp, > + bool *error_is_set_sndbuf) > { > Error *err =3D NULL; > TAPState *s =3D net_tap_fd_init(peer, model, name, fd, vnet_hdr); > @@ -651,6 +652,9 @@ static void net_init_tap_one(const NetdevTapOptions= *tap, NetClientState *peer, > tap_set_sndbuf(s->fd, tap, &err); > if (err) { > error_propagate(errp, err); > + if (error_is_set_sndbuf) { > + *error_is_set_sndbuf =3D true; > + } > return; > } > =20 > @@ -748,6 +752,7 @@ int net_init_tap(const Netdev *netdev, const char *= name, > Error *err =3D NULL; > const char *vhostfdname; > char ifname[128]; > + bool error_is_set_sndbuf =3D false; > =20 > assert(netdev->type =3D=3D NET_CLIENT_DRIVER_TAP); > tap =3D &netdev->u.tap; > @@ -783,7 +788,7 @@ int net_init_tap(const Netdev *netdev, const char *= name, > =20 > net_init_tap_one(tap, peer, "tap", name, NULL, > script, downscript, > - vhostfdname, vnet_hdr, fd, &err); > + vhostfdname, vnet_hdr, fd, &err, NULL); > if (err) { > error_propagate(errp, err); > return -1; > @@ -835,7 +840,7 @@ int net_init_tap(const Netdev *netdev, const char *= name, > net_init_tap_one(tap, peer, "tap", name, ifname, > script, downscript, > tap->has_vhostfds ? vhost_fds[i] : NULL, > - vnet_hdr, fd, &err); > + vnet_hdr, fd, &err, NULL); > if (err) { > error_propagate(errp, err); > goto free_fail; > @@ -874,10 +879,13 @@ free_fail: > =20 > net_init_tap_one(tap, peer, "bridge", name, ifname, > script, downscript, vhostfdname, > - vnet_hdr, fd, &err); > + vnet_hdr, fd, &err, &error_is_set_sndbuf); > if (err) { > error_propagate(errp, err); > - close(fd); > + if (error_is_set_sndbuf || (tap->has_vhostforce && > + tap->vhostforce)) { > + close(fd); > + } > return -1; > } > } else { > @@ -913,10 +921,14 @@ free_fail: > net_init_tap_one(tap, peer, "tap", name, ifname, > i >=3D 1 ? "no" : script, > i >=3D 1 ? "no" : downscript, > - vhostfdname, vnet_hdr, fd, &err); > + vhostfdname, vnet_hdr, fd, &err, > + &error_is_set_sndbuf); > if (err) { > error_propagate(errp, err); > - close(fd); > + if (error_is_set_sndbuf || (tap->has_vhostforce && > + tap->vhostforce)) { > + close(fd); > + } > return -1; > } > } > > > > PS: I think I do not express the meaning clearly... I can express it in > Chinese in private if necessary > > Regards, > Jay That's kind of ugly. I would suggest do all the correct thing in net_tap_init_one(). Thanks