From: Al Viro <viro@ZenIV.linux.org.uk>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jason Wang <jasowang@redhat.com>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] macvtap: advance iov iterator when needed in macvtap_put_user()
Date: Thu, 20 Nov 2014 08:41:52 +0000 [thread overview]
Message-ID: <20141120084152.GL7996@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20141120083426.GA30001@gondor.apana.org.au>
On Thu, Nov 20, 2014 at 04:34:26PM +0800, Herbert Xu wrote:
> On Thu, Nov 20, 2014 at 04:31:05PM +0800, Jason Wang wrote:
> > When mergeable buffer is used, vnet_hdr_sz is greater than sizeof struct
> > virtio_net_hdr. So we need advance the iov iterators in this case.
> >
> > Fixes 6c36d2e26cda1ad3e2c4b90dd843825fc62fe5b4 ("macvtap: Use iovec iterators")
> > Cc: Herbert Xu <herbert@gondor.apana.org.au>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
>
> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
I'm not sure it's a good behaviour, actually - should we just leave an
unmodified gap in userland buffer there, with whatever garbage it might
have contained?
I do realize that this is what we used to do, but it might end up a source
of hard to debug userland bugs... Perhaps that iov_iter_advance(iter, size)
would better be replaced with iov_iter_zero(size, iter)?
next prev parent reply other threads:[~2014-11-20 8:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 8:31 [PATCH net-next] macvtap: advance iov iterator when needed in macvtap_put_user() Jason Wang
2014-11-20 8:34 ` Herbert Xu
2014-11-20 8:41 ` Al Viro [this message]
2014-11-20 8:53 ` Jason Wang
2014-11-21 19:59 ` David Miller
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