linux/include
Michael S. Tsirkin d9d52b5178 tun: add ioctl to modify vnet header size
virtio added mergeable buffers mode where 2 bytes of extra info is put
after vnet header but before actual data (tun does not need this data).
In hindsight, it would have been better to add the new info *before* the
packet: as it is, users need a lot of tricky code to skip the extra 2
bytes in the middle of the iovec, and in fact applications seem to get
it wrong, and only work with specific iovec layout.  The fact we might
need to split iovec also means we might in theory overflow iovec max
size.

This patch adds a simpler way for applications to handle this,
and future proofs the interface against further extensions,
by making the size of the virtio net header configurable
from userspace. As a result, tun driver will simply
skip the extra 2 bytes on both input and output.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
2010-05-03 12:33:13 +03:00
..
acpi acpi: Support IBM SMBus CMI devices 2010-03-24 14:38:37 +01:00
asm-generic dma-mapping: pci: move pci_set_dma_mask and pci_set_consistent_dma_mask to pci-dma-compat.h 2010-03-12 15:52:42 -08:00
crypto
drm Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-04-19 07:27:06 -07:00
keys
linux tun: add ioctl to modify vnet header size 2010-05-03 12:33:13 +03:00
math-emu Fix misspellings of "truly" in comments. 2010-02-04 11:55:45 +01:00
media Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
mtd
net Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-05-02 22:02:06 -07:00
pcmcia pcmcia: use dev_pm_ops for class pcmcia_socket_class 2010-03-24 11:00:11 +01:00
rdma Merge branch 'misc' into for-next 2010-03-01 23:52:31 -08:00
rxrpc
scsi include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sound Merge branch 'fix/asoc' into for-linus 2010-04-07 09:54:41 +02:00
trace Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-04-09 11:50:29 -07:00
video broadsheetfb: support storing waveform 2010-03-12 15:52:34 -08:00
xen include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kbuild