• Neil Horman's avatar
    netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock · 2cde6acd
    Neil Horman authored
    __netpoll_rcu_free is used to free netpoll structures when the rtnl_lock is
    already held.  The mechanism is used to asynchronously call __netpoll_cleanup
    outside of the holding of the rtnl_lock, so as to avoid deadlock.
    Unfortunately, __netpoll_cleanup modifies pointers (dev->np), which means the
    rtnl_lock must be held while calling it.  Further, it cannot be held, because
    rcu callbacks may be issued in softirq contexts, which cannot sleep.
    
    Fix this by converting the rcu callback to a work queue that is guaranteed to
    get scheduled in process context, so that we can hold the rtnl properly while
    calling __netpoll_cleanup
    
    Tested successfully by myself.
    Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
    CC: "David S. Miller" <davem@davemloft.net>
    CC: Cong Wang <amwang@redhat.com>
    CC: Eric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    2cde6acd
bond_main.c 132 KB