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Date:   Wed, 14 Mar 2018 21:08:46 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Bart Van Assche <Bart.VanAssche@wdc.com>
Cc:     "tj@kernel.org" <tj@kernel.org>,
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        "axboe@kernel.dk" <axboe@kernel.dk>,
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Subject: Re: [PATCH 5/7] block: Remove superflous rcu_read_[un]lock_sched()
 in blk_queue_enter()
Message-ID: <20180314200846.GR4064@hirez.programming.kicks-ass.net>
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On Wed, Mar 14, 2018 at 08:05:30PM +0000, Bart Van Assche wrote:
> Can you clarify this further? From <linux/rcupdate.h>:
> 
> static inline void synchronize_rcu(void)
> {
> 	synchronize_sched();
> }

You'll find that is for !CONFIG_PREEMPT_RCU.