[dpdk-dev] [PATCH 0/3] Vhost app removes dependency of REFCNT

[Ouyang Changchun <changchun.ouyang@intel.com>]

To remove the dependency of RTE_MBUF_REFCNT for vhost zero copy,
the mbuf need introduce EXTERNAL_MBUF(in ol_flags) to indicate it
attaches to an external buffer, say, from guest space. And don't
free the external buffer when freeing the mbuf itself in host, in
addition, RX function in PMD need make sure not overwrite this flag
when filling ol_flags from descriptors to mbuf.

Changchun Ouyang (3):
  mbuf use EXTERNAL_MBUF in ol_flags to indicate it is an external
    buffer,     when freeing such kind of mbuf, just need put mbuf
    itself back into mempool,     doesn't free the attached external
    buffer, user/caller need take care of     detaching and freeing the
    external buffer.
  Every pmd RX function need keep the EXTERNAL_MBUF flag in
    mbuf.ol_flags,     and can't overwrite it when filling ol_flags from
    descriptor to mbuf,     otherwise, it probably cause to crash when
    freeing a mbuf and trying     to freeing its attached external
    buffer, say, from guest space.
  vhost zero copy removes the dependency on macro REFCNT by using
    EXTERNAL_MBUF     flag in mbuf.ol_flags to indicate it is an
    external buffer from guest.

 examples/vhost/main.c                 | 19 +++++--------------
 lib/librte_mbuf/rte_mbuf.h            |  5 ++++-
 lib/librte_pmd_e1000/igb_rxtx.c       |  5 +++--
 lib/librte_pmd_i40e/i40e_rxtx.c       |  8 +++++---
 lib/librte_pmd_ixgbe/ixgbe_rxtx.c     |  8 +++++---
 lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 12 ++++++++----
 6 files changed, 30 insertions(+), 27 deletions(-)

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1.8.4.2