From mboxrd@z Thu Jan  1 00:00:00 1970
From: keith.busch@intel.com (Keith Busch)
Date: Fri, 22 May 2015 14:48:13 +0000 (UTC)
Subject: [PATCH] NVMe: Avoid interrupt disable during queue init.
In-Reply-To: <CAGgvQNQHaZBRzedkLmYxCBtDyxq7j2wr=e0vAYfw5r+KKeVbxg@mail.gmail.com>
References: <1432253553-17045-1-git-send-email-parav.pandit@avagotech.com>
 <alpine.LNX.2.00.1505211931470.15930@localhost.lm.intel.com>
 <CAGgvQNQHaZBRzedkLmYxCBtDyxq7j2wr=e0vAYfw5r+KKeVbxg@mail.gmail.com>
Message-ID: <alpine.LNX.2.00.1505221446410.15930@localhost.lm.intel.com>

On Thu, 21 May 2015, Parav Pandit wrote:
> On Fri, May 22, 2015@1:04 AM, Keith Busch <keith.busch@intel.com> wrote:
>> The q_lock is held to protect polling from reading inconsistent data.
>
> ah, yes. I can see the nvme_kthread can poll the CQ while its getting
> created through the nvme_resume().
> I think this opens up other issue.
>
> nvme_kthread() should,
>
> Instead of,
> struct nvme_queue *nvmeq = dev->queues[i];
>
> it should do,
> struct nvme_queue *nvmeq = rcu_dereference(dev->queues[i]);

The rcu protection on nvme queues was removed with the blk-mq conversion
as we rely on that layer for h/w access.