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From:   Denys Vlasenko <vda.linux@googlemail.com>
Date:   Tue, 5 Feb 2019 19:34:31 +0100
Message-ID: <CAK1hOcN8_0MNEFfoHg0sAuu09SPhXHvXfXkeHONtoFXOArjumg@mail.gmail.com>
Subject: preempt.h: some SOFTIRQ_OFFSET should be SOFTIRQ_MASK?
To:     Frederic Weisbecker <fweisbec@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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SOFTIRQ is a counter.
Why here:

#define in_serving_softirq()    (softirq_count() & SOFTIRQ_OFFSET)
#define in_task()               (!(preempt_count() & \
                                   (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))

we check only lowest bit?