• Roman Pen's avatar
    percpu-refcount: init ->confirm_switch member properly · a67823c1
    Roman Pen authored
    This patch targets two things which are related to ->confirm_switch:
    
     1. Init ->confirm_switch pointer with NULL on percpu_ref_init() or
        kernel frightfully complains with WARN_ON_ONCE(ref->confirm_switch)
        at __percpu_ref_switch_to_atomic if memory chunk was not properly
        zeroed.
    
     2. Warn if RCU callback is still in progress on percpu_ref_exit().
        The race still exists, because percpu_ref_call_confirm_rcu()
        drops ->confirm_switch to NULL early, but that is only a warning
        and still the caller is responsible that ref is no longer in
        active use.  Hopefully that can help to catch incorrect usage
        of percpu-refcount.
    Signed-off-by: 's avatarRoman Pen <roman.penyaev@profitbricks.com>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: 's avatarTejun Heo <tj@kernel.org>
    a67823c1