Messages in this thread | | | Date | Thu, 20 Nov 2014 08:41:52 +0000 | From | Al Viro <> | Subject | Re: [PATCH net-next] macvtap: advance iov iterator when needed in macvtap_put_user() |
| |
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)?
| |