From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amos Kong Subject: Re: [PATCH net-next] tun: return NET_XMIT_DROP for dropped packets Date: Wed, 19 Nov 2014 00:53:59 +0800 Message-ID: <20141118165359.GA18636@air.redhat.com> References: <1416288041-30921-1-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4Ckj6UjgE2iN1+kY" Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Michael S. Tsirkin" To: Jason Wang Return-path: Content-Disposition: inline In-Reply-To: <1416288041-30921-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --4Ckj6UjgE2iN1+kY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Nov 18, 2014 at 01:20:41PM +0800, Jason Wang wrote: > After commit 5d097109257c03a71845729f8db6b5770c4bbedc > ("tun: only queue packets on device"), NETDEV_TX_OK was returned for > dropped packets. This will confuse pktgen since dropped packets were > counted as sent ones. >=20 > Fixing this by returning NET_XMIT_DROP to let pktgen count it as error > packet. >=20 > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > drivers/net/tun.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index e3fa65a..ac53a73 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -819,7 +819,7 @@ drop: > skb_tx_error(skb); > kfree_skb(skb); > rcu_read_unlock(); > - return NETDEV_TX_OK; > + return NET_XMIT_DROP; Quoted from linux/drivers/firewire/net.c: /* * FIXME: According to a patch from 2003-02-26, "returning non-zero * causes serious problems" here, allegedly. Before that patch, * -ERRNO was returned which is not appropriate under Linux 2.6. * Perhaps more needs to be done? Stop the queue in serious * conditions and restart it elsewhere? */ I saw many drivers return NETDEV_TX_OK in xmit for drop packets, eg: virtio= _net.c > } > =20 > static void tun_net_mclist(struct net_device *dev) > --=20 > 1.9.1 --=20 Amos. --4Ckj6UjgE2iN1+kY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUa3mnAAoJELxSv6I5vP9jNM8P/1xRnuF/aufE6HbA/VcK0X1x AK/SIhc9b/vZ7UxU19kBHXMuvEEmyKhhQEqOYxIPIEXfaKuVBOq0rqfIIknFbQiK V1Km99ltlk+nq2mBbadGLm/l2Y3ZiACGShlbZisWhQL1QkR8gC3OGZGfJ0I/5QWd f4woJQD1w3K033Re6YG8WUCf0+NOXPF1VfT8emD38KktuhPIO5rpIP3kVxI/7uVJ s/ZxFYIIs6w6vrU9gaf2NZrNPuAjjtuAPRmk6yDjaBWQvjxgMKuQ0Nw0jh47kkdm IXYAlagvxRbbe2StduayjpuSFZbWJhfBs0ubC+nKeOV2Cr+QWSQcSTddareDWYFk SKEUcNjdSPOOCdPut1c/4g+jbdhKhhIliZV981DOu133/wUGhH7uCMO6rqlFw24I O6BGccl9YovTGcNbQMG+SQx6giB3zw5kLS5inmfjJHh4vlbuBSEMbfArIm7tzRwD UDdqpla50XUT/U7SVD29hjcLNP1jtZgM7yI9qXkoQ8o1SqrWWiDd1DNnpeU1ris/ SoiNxf7jzREPIFfsVcAihc6U+HrraS9XyEY9JrHBjMRXIrcnmZ0sZwQ1csutyn1c r9mU3y2Heh8G4wmuQYIhz15KlzAwUO7PELUpjz15IGbZIihQuUD4YovCGU+nEdgu zSEFdXhurBLxpc9iF9zM =MFYZ -----END PGP SIGNATURE----- --4Ckj6UjgE2iN1+kY--