From: Keith Busch <keith.busch@intel.com>
To: Parav Pandit <parav.pandit@avagotech.com>
Cc: Keith Busch <keith.busch@intel.com>,
linux-nvme@lists.infradead.org,
Matthew Wilcox <willy@linux.intel.com>,
Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] NVMe: Avoid interrupt disable during queue init.
Date: Fri, 22 May 2015 17:07:22 +0000 (UTC) [thread overview]
Message-ID: <alpine.LNX.2.00.1505221700120.15930@localhost.lm.intel.com> (raw)
In-Reply-To: <CAGgvQNTHyLZzOdi9m5FPfwwsRtxhrvf48Uz590RNsPVkw+HMNw@mail.gmail.com>
On Fri, 22 May 2015, Parav Pandit wrote:
> On Fri, May 22, 2015 at 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.
next prev parent reply other threads:[~2015-05-22 17:07 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-22 0:12 [PATCH] NVMe: Avoid interrupt disable during queue init Parav Pandit
2015-05-21 18:39 ` Jens Axboe
2015-05-21 19:14 ` Parav Pandit
2015-05-21 19:34 ` Keith Busch
2015-05-22 4:15 ` Parav Pandit
2015-05-22 14:48 ` Keith Busch
2015-05-22 14:51 ` Parav Pandit
2015-05-22 15:11 ` Keith Busch
2015-05-22 16:03 ` Parav Pandit
2015-05-22 16:23 ` Keith Busch
2015-05-22 16:48 ` Parav Pandit
2015-05-22 17:07 ` Keith Busch [this message]
2015-05-22 17:33 ` Parav Pandit
2015-05-22 17:47 ` Keith Busch
2015-05-22 18:18 ` Parav Pandit
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