+++ This bug was initially created as a clone of Bug #1573912 +++

Would like to have the following DPDK commit in RHEL 7.6. Not sure how the process works for DPDK, feel free to educate me:

commit 0c0e46c36bcc5dfe9d2aa605e1a5f714d45e0b7f
Author: Alejandro Lucero <alejandro.lucero>
Date:   Mon Apr 23 12:23:58 2018 +0100

    net/nfp: fix mbufs releasing when stop or close
    
    PMDs have the responsibility of releasing mbufs sent through xmit burst
    function. NFP PMD attaches those sent mbufs to the TX ring structure,
    and it is at the next time a specific ring descriptor is going to be
    used when the previous linked mbuf, already transmitted at that point,
    is released. Those mbufs belonging to a chained mbuf got its own link
    to a ring descriptor, and they are released independently of the mbuf
    head of that chain.
    
    The problem is how those mbufs are released when the PMD is stopped or
    closed. Instead of releasing those mbufs as the xmit functions does,
    this is independently of being in a mbuf chain, the code calls
    rte_pktmbuf_free which will release not just the mbuf head in that
    chain but all the chained mbufs. The loop will try to release those
    mbufs which have already been released again when chained mbufs exist.
    
    This patch fixes the problem using rte_pktmbuf_free_seg instead.
    
    Fixes: b812daadad0d ("nfp: add Rx and Tx")
    Cc: stable
    
    Signed-off-by: Alejandro Lucero <alejandro.lucero>