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Date: Fri, 6 Dec 2013 02:56:39 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
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        David Daney <david.daney@cavium.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: smp_call_function_single with wait=0 considered harmful
Message-ID: <20131206105639.GA20448@infradead.org>
References: <20131204164627.GA27677@infradead.org>
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On Thu, Dec 05, 2013 at 02:43:03PM -0700, Bjorn Helgaas wrote:
> smp_call_function_single() sets "csd = &__get_cpu_var(csd_data)", so
> it's not using a struct on the stack.  We'll queue up "func" and
> likely will return before it is executed, but that should be fine
> because nobody will overwrite csd_data until it *is* executed and
> csd_unlock() has been called.

You're right, I missed the usage of the per-cpu data later in the
function.