From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net-next] tun/macvtap: use consume_skb() instead of kfree_skb() in tun/macvtap_do_read() Date: Wed, 26 Nov 2014 14:41:43 +0800 Message-ID: <54757627.7060105@redhat.com> References: <1416982084-12212-1-git-send-email-jasowang@redhat.com> <1416983160.29427.52.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com To: Eric Dumazet Return-path: In-Reply-To: <1416983160.29427.52.camel@edumazet-glaptop2.roam.corp.google.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 11/26/2014 02:26 PM, Eric Dumazet wrote: > On Wed, 2014-11-26 at 14:08 +0800, Jason Wang wrote: >> To be more friendly with drop monitor, we should use comsume_skb() instead >> of kfree_skb() in tun/macvtap_do_read(). Otherwise, the packets will be >> marked as dropped. >> >> Signed-off-by: Jason Wang >> --- >> drivers/net/macvtap.c | 2 +- >> drivers/net/tun.c | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c >> index 42a80d3..74d1b23 100644 >> --- a/drivers/net/macvtap.c >> +++ b/drivers/net/macvtap.c >> @@ -862,7 +862,7 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q, >> } >> iov_iter_init(&iter, READ, iv, segs, len); >> ret = macvtap_put_user(q, skb, &iter); >> - kfree_skb(skb); >> + consume_skb(skb); >> break; >> } >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index ac53a73..d7edeaf 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1363,7 +1363,7 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, >> >> iov_iter_init(&iter, READ, iv, segs, len); >> ret = tun_put_user(tun, tfile, skb, &iter); >> - kfree_skb(skb); >> + consume_skb(skb); >> >> return ret; >> } > > These patches keep going on, but they are wrong. > > If you care about drop monitor, then you want to not hide drops but > precisely report them. > > Surely tun_put_user() can return an error, and then packet _is_ dropped. True, I miss this. Will post V2. Thanks