• Debabrata Banerjee's avatar
    netpoll: allow cleanup to be synchronous · c9fbd71f
    Debabrata Banerjee authored
    This fixes a problem introduced by:
    commit 2cde6acd ("netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock")
    When using netconsole on a bond, __netpoll_cleanup can asynchronously
    recurse multiple times, each __netpoll_free_async call can result in
    more __netpoll_free_async's. This means there is now a race between
    cleanup_work queues on multiple netpoll_info's on multiple devices and
    the configuration of a new netpoll. For example if a netconsole is set
    to enable 0, reconfigured, and enable 1 immediately, this netconsole
    will likely not work.
    Given the reason for __netpoll_free_async is it can be called when rtnl
    is not locked, if it is locked, we should be able to execute
    synchronously. It appears to be locked everywhere it's called from.
    Generalize the design pattern from the teaming driver for current
    callers of __netpoll_free_async.
    CC: Neil Horman <nhorman@tuxdriver.com>
    CC: "David S. Miller" <davem@davemloft.net>
    Signed-off-by: Debabrata Banerjee's avatarDebabrata Banerjee <dbanerje@akamai.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
netpoll.h 2.69 KB