linux.git/include/linux/if_tun.h, branch v7.2-rc1

vhost-net: wake queue of tun/tap after ptr_ring consume

2026-05-14T00:52:55+00:00

Add tun_wake_queue() to tun.c and export it for use by vhost-net. The
function validates that the file belongs to a tun/tap device and that
the tfile exists, dereferences the tun_struct under RCU, and delegates
to __tun_wake_queue().

vhost_net_buf_produce() now calls tun_wake_queue() after a successful
batched consume of the ring to allow the netdev subqueue to be woken up.
The point is to allow the queue to be stopped when it gets full, which
is required for traffic shaping - implemented by the following
"avoid ptr_ring tail-drop when a qdisc is present".

Without the corresponding queue stopping, this patch alone causes no
throughput regression for a tap+vhost-net setup sending to a qemu VM:
3.857 Mpps to 3.891 Mpps.

Details: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU
threads, XDP drop program active in VM, pktgen sender; Avg over
50 runs @ 100,000,000 packets. SRSO and spectre v2 mitigations disabled.

Co-developed-by: Tim Gebauer 
Signed-off-by: Tim Gebauer 
Signed-off-by: Simon Schippers 
Acked-by: Michael S. Tsirkin 
Link: https://patch.msgid.link/20260510151529.43895-3-simon.schippers@tu-dortmund.de
Signed-off-by: Jakub Kicinski

tun: remove unnecessary tun_xdp_hdr structure

2025-07-02T22:29:46+00:00

With f95f0f95cfb7("net, xdp: Introduce xdp_init_buff utility routine"),
buffer length could be stored as frame size so there's no need to have
a dedicated tun_xdp_hdr structure. We can simply store virtio net
header instead.

Acked-by: Willem de Bruijn 
Signed-off-by: Jason Wang 
Link: https://patch.msgid.link/20250701010352.74515-1-jasowang@redhat.com
Signed-off-by: Jakub Kicinski

tun: Fix code style issues in

2024-02-04T15:41:18+00:00

This fixes the following code style problem:
- WARNING: please, no spaces at the start of a line
- CHECK: Please use a blank line after
         function/struct/union/enum declarations

Signed-off-by: Yunjian Wang 
Reviewed-by: Jiri Pirko 
Reviewed-by: Willem de Bruijn 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller

net-tun: Eliminate two tun/xdp related function calls from vhost-net

2020-08-19T21:02:49+00:00

This provides a minor performance boost by virtue of inlining
instead of cross module function calls.

Test: builds

Signed-off-by: Maciej Żenczykowski 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200819010710.3959310-2-zenczykowski@gmail.com

net-tun: Add type safety to tun_xdp_to_ptr() and tun_ptr_to_xdp()

2020-08-19T21:02:49+00:00

This reduces likelihood of incorrect use.

Test: builds

Signed-off-by: Maciej Żenczykowski 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200819010710.3959310-1-zenczykowski@gmail.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

2019-05-30T18:26:37+00:00

Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman

tun: switch to new type of msg_control

2018-09-13T16:25:40+00:00

This patch introduces to a new tun/tap specific msg_control:

#define TUN_MSG_UBUF 1
#define TUN_MSG_PTR  2
struct tun_msg_ctl {
       int type;
       void *ptr;
};

This allows us to pass different kinds of msg_control through
sendmsg(). The first supported type is ubuf (TUN_MSG_UBUF) which will
be used by the existed vhost_net zerocopy code. The second is XDP
buff, which allows vhost_net to pass XDP buff to TUN. This could be
used to implement accepting an array of XDP buffs from vhost_net in
the following patches.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

tun: convert to use generic xdp_frame and xdp_return_frame API

2018-04-17T14:50:28+00:00

The tuntap driver invented it's own driver specific way of queuing
XDP packets, by storing the xdp_buff information in the top of
the XDP frame data.

Convert it over to use the more generic xdp_frame structure.  The
main problem with the in-driver method is that the xdp_rxq_info pointer
cannot be trused/used when dequeueing the frame.

V3: Remove check based on feedback from Jason

Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: David S. Miller

vhost_net: examine pointer types during un-producing

2018-03-09T17:02:59+00:00

After commit fc72d1d54dd9 ("tuntap: XDP transmission"), we can
actually queueing XDP pointers in the pointer ring, so we should
examine the pointer type before freeing the pointer.

Fixes: fc72d1d54dd9 ("tuntap: XDP transmission")
Reported-by: Michael S. Tsirkin 
Acked-by: Michael S. Tsirkin 
Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

tuntap: fix for "tuntap: XDP transmission"

2018-01-10T20:52:49+00:00

Fixes: fc72d1d54dd9 ("tuntap: XDP transmission")
Signed-off-by: Stephen Rothwell 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller