From: Bart Van Assche <bvanassche@acm.org>
To: "Singh, Balbir" <sblbir@amazon.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"sblbir@amzn.com" <sblbir@amzn.com>
Cc: "kbusch@kernel.org" <kbusch@kernel.org>,
"axboe@fb.com" <axboe@fb.com>, "hch@lst.de" <hch@lst.de>,
"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH v2 1/2] nvme/host/pci: Fix a race in controller removal
Date: Tue, 17 Sep 2019 10:55:45 -0700 [thread overview]
Message-ID: <eeefce01-3d9d-ade1-50e1-79e3dca76fcc@acm.org> (raw)
In-Reply-To: <7a90bbc89594dd884b055cec3dc5f3060f1b1e5c.camel@amazon.com>
On 9/16/19 1:40 PM, Singh, Balbir wrote:
> Is your concern largely with the comment or the patch?
>
> Keith just recommend added
>
> /* Revalidate after unblocking dispatchers that may be holding bd_butex */
>
> That sounds quite reasonable to me
Hi Balbir,
Keith's comment suggestion sounds great to me.
Another concern I have is that your patch depends on implementation
details of the block layer. Calling revalidate_disk() after the DYING
flag has been set means that requests will be allocated, started and
completed after the DYING flag has been set. I think that works with the
current implementation of the block layer because blk_queue_enter() does
not check the DYING flag if percpu_ref_tryget_live() succeeds. If your
patch gets accepted and if blk_queue_enter() would be modified such that
the DYING flag is checked for every blk_queue_enter() call then that
would break the NVMe driver.
Thanks,
Bart.
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next prev parent reply other threads:[~2019-09-17 17:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 23:36 [PATCH v2 1/2] nvme/host/pci: Fix a race in controller removal Balbir Singh
2019-09-13 23:36 ` [PATCH v2 2/2] nvme/host/core: Allow overriding of wait_ready timeout Balbir Singh
2019-09-16 7:41 ` Christoph Hellwig
2019-09-16 12:33 ` Singh, Balbir
2019-09-16 16:01 ` hch
2019-09-16 21:04 ` Singh, Balbir
2019-09-17 1:14 ` Keith Busch
2019-09-17 2:56 ` Singh, Balbir
2019-09-17 3:17 ` Bart Van Assche
2019-09-17 5:02 ` Singh, Balbir
2019-09-17 17:21 ` James Smart
2019-09-17 20:08 ` James Smart
2019-09-17 3:54 ` Keith Busch
2019-09-16 7:49 ` [PATCH v2 1/2] nvme/host/pci: Fix a race in controller removal Christoph Hellwig
2019-09-16 12:07 ` Singh, Balbir
2019-09-16 15:40 ` Bart Van Assche
2019-09-16 19:38 ` Singh, Balbir
2019-09-16 19:56 ` Bart Van Assche
2019-09-16 20:40 ` Singh, Balbir
2019-09-17 17:55 ` Bart Van Assche [this message]
2019-09-17 20:30 ` Keith Busch
2019-09-17 20:44 ` Singh, Balbir
2019-09-16 20:07 ` Keith Busch
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