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    SubjectRe: [PATCH v4 01/27] lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions
    On Fri, Feb 21, 2020 at 09:25:11PM +0100, Peter Zijlstra wrote:
    > On Fri, Feb 21, 2020 at 10:08:55AM -0500, Steven Rostedt wrote:
    > > On Fri, 21 Feb 2020 14:34:17 +0100
    > > Peter Zijlstra <peterz@infradead.org> wrote:
    > >
    > > > --- a/kernel/locking/lockdep.c
    > > > +++ b/kernel/locking/lockdep.c
    > > > @@ -379,13 +379,13 @@ void lockdep_init_task(struct task_struc
    > > >
    > > > void lockdep_off(void)
    > > > {
    > > > - current->lockdep_recursion++;
    > > > + current->lockdep_recursion += BIT(16);
    > > > }
    > > > EXPORT_SYMBOL(lockdep_off);
    > > >
    > > > void lockdep_on(void)
    > > > {
    > > > - current->lockdep_recursion--;
    > > > + current->lockdep_recursion -= BIT(16);
    > > > }
    > > > EXPORT_SYMBOL(lockdep_on);
    > > >
    > >
    > > > +
    > > > +static bool lockdep_nmi(void)
    > > > +{
    > > > + if (current->lockdep_recursion & 0xFFFF)
    > >
    > > Nitpick, but the association with bit 16 and this mask really should be
    > > defined as a macro somewhere and not have hard coded numbers.
    >
    > Right, I suppose I can do something like:
    >
    > #define LOCKDEP_RECURSION_BITS 16
    > #define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS)
    > #define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1)

    With that I'd say

    Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

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