From mboxrd@z Thu Jan  1 00:00:00 1970
From: keith.busch@intel.com (Keith Busch)
Date: Fri, 22 May 2015 17:07:22 +0000 (UTC)
Subject: [PATCH] NVMe: Avoid interrupt disable during queue init.
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On Fri, 22 May 2015, Parav Pandit wrote:
> On Fri, May 22, 2015@9:53 PM, Keith Busch <keith.busch@intel.com> wrote:
>> A memory barrier before incrementing the dev->queue_count (and assigning
>> the pointer in the array before that) should address this concern.
>
> Sure. mb() will solve the publisher side problem. RCU is wrapper around mb().
> However mb() doesn't solve the issue of q_lock variable getting
> fetched before if (!nvmeq) condition being executed, by value
> compilation optimizations in nvme_kthread().

Eh? The value of dev->queue_count prevents the thread's for-loop from
iterating that nvmeq before the q_lock is initialized.