From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934233AbdC3PGi (ORCPT ); Thu, 30 Mar 2017 11:06:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47964 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933709AbdC3PGg (ORCPT ); Thu, 30 Mar 2017 11:06:36 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D91EB8049E Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mst@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com D91EB8049E Date: Thu, 30 Mar 2017 18:06:28 +0300 From: "Michael S. Tsirkin" To: Jason Wang Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2 net-next 5/7] tun: support receiving skb through msg_control Message-ID: <20170330180414-mutt-send-email-mst@kernel.org> References: <1490858550-7763-1-git-send-email-jasowang@redhat.com> <1490858550-7763-6-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490858550-7763-6-git-send-email-jasowang@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 30 Mar 2017 15:06:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 30, 2017 at 03:22:28PM +0800, Jason Wang wrote: > This patch makes tun_recvmsg() can receive from skb from its caller > through msg_control. Vhost_net will be the first user. > > Signed-off-by: Jason Wang Do we need to bother with tun? I didn't realize one can even use that with vhost. What would be the point of all the virtio header stuff dealing with checksums etc? Even if you see a use-case is it worth optimizing? > --- > drivers/net/tun.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 70dd9ec..a82bced 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1498,9 +1498,8 @@ static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock, > > static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, > struct iov_iter *to, > - int noblock) > + int noblock, struct sk_buff *skb) > { > - struct sk_buff *skb; > ssize_t ret; > int err; > > @@ -1509,10 +1508,12 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, > if (!iov_iter_count(to)) > return 0; > > - /* Read frames from ring */ > - skb = tun_ring_recv(tfile, noblock, &err); > - if (!skb) > - return err; > + if (!skb) { > + /* Read frames from ring */ > + skb = tun_ring_recv(tfile, noblock, &err); > + if (!skb) > + return err; > + } > > ret = tun_put_user(tun, tfile, skb, to); > if (unlikely(ret < 0)) > @@ -1532,7 +1533,7 @@ static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) > > if (!tun) > return -EBADFD; > - ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); > + ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL); > ret = min_t(ssize_t, ret, len); > if (ret > 0) > iocb->ki_pos = ret; > @@ -1634,7 +1635,8 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, > SOL_PACKET, TUN_TX_TIMESTAMP); > goto out; > } > - ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); > + ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, > + m->msg_control); > if (ret > (ssize_t)total_len) { > m->msg_flags |= MSG_TRUNC; > ret = flags & MSG_TRUNC ? ret : total_len; > -- > 2.7.4