[ovs-git] [openvswitch/ovs] 71417e: netdev-dpdk: linear buffer check with zero-copy

[istokes]

  Branch: refs/heads/master
  Home:   https://github.com/openvswitch/ovs
  Commit: 71417ef0119e1b522edf928b453753ab8ab513d9
      https://github.com/openvswitch/ovs/commit/71417ef0119e1b522edf928b453753ab8ab513d9
  Author: Sivaprasad Tummala <Sivaprasad.Tummala at intel.com>
  Date:   2020-08-12 (Wed, 12 Aug 2020)

  Changed paths:
    M lib/netdev-dpdk.c

  Log Message:
  -----------
  netdev-dpdk: linear buffer check with zero-copy

As of DPDK 19.11, in order to use dequeue-zero-copy in DPDK Vhost library,
the application has to disable the linear buffer option. Hence
dequeue-zero-copy is not supported for vhost application that requires
linear buffers.

An alternative DPDK based approach to disable the linear buffers within
the vhost library itself was proposed in [1], however the consensus was
that application should be responsible for disabling linear buffers.

As such this patch disables linear buffers when zero-copy is enabled.

[1]    https://patches.dpdk.org/patch/67200/

Fixes: 127b6a6eea02 ("dpdk: Update to use DPDK 19.11.")
Signed-off-by: Sivaprasad Tummala <Sivaprasad.Tummala at intel.com>
Acked-by: Ilya Maximets <i.maximets at ovn.org>
Signed-off-by: Ian Stokes <ian.stokes at intel.com>


  Commit: e919fd4955f86de827e128808fe1a4c34e788947
      https://github.com/openvswitch/ovs/commit/e919fd4955f86de827e128808fe1a4c34e788947
  Author: Ian Stokes <ian.stokes at intel.com>
  Date:   2020-08-12 (Wed, 12 Aug 2020)

  Changed paths:
    M Documentation/topics/dpdk/vhost-user.rst
    M NEWS
    M lib/netdev-dpdk.c

  Log Message:
  -----------
  dpdk: Deprecate vhost-user dequeue zero-copy.

Dequeue zero-copy is no longer supported for vhost-user client mode
in DPDK due to commit [1].

In addition to this, zero-copy mode has been proposed to be marked
deprecated in [2] with removal in the next DPDK LTS release.

This commit deprecates support for vhost-user dequeue zero-copy in OVS
with its removal expected in the next OVS release.

[1] 715070ea10e6 ("vhost: prevent zero-copy with incompatible client
    mode")
[2] http://mails.dpdk.org/archives/dev/2020-August/177236.html

Signed-off-by: Ian Stokes <ian.stokes at intel.com>
Acked-by: Maxime Coquelin <maxime.coquelin at redhat.com>
Acked-by: Ilya Maximets <i.maximets at ovn.org>


Compare: https://github.com/openvswitch/ovs/compare/b8d42f875c8c...e919fd4955f8