Messages in this thread | | | Date | Fri, 18 Sep 2020 12:04:32 +0200 | From | peterz@infradea ... | Subject | Re: [RFC PATCH] locking/percpu-rwsem: use this_cpu_{inc|dec}() for read_count |
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On Fri, Sep 18, 2020 at 12:01:12PM +0200, peterz@infradead.org wrote: > @@ -198,7 +198,9 @@ EXPORT_SYMBOL_GPL(__percpu_down_read); > */ > static bool readers_active_check(struct percpu_rw_semaphore *sem) > { > - if (per_cpu_sum(*sem->read_count) != 0) > + u64 sum = per_cpu_sum(*(u64 *)sem->read_count); > + > + if (sum + (sum >> 32))
That obviously wants to be:
if ((u32)(sum + (sum >> 32)))
> return false; > > /*
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