Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v2 5/5] nvme-fc: Freeze queues before destroying them
To:     Daniel Wagner <dwagner@suse.de>, linux-nvme@lists.infradead.org
Cc:     linux-kernel@vger.kernel.org,
        James Smart <james.smart@broadcom.com>,
        Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
        Ming Lei <ming.lei@redhat.com>,
        Sagi Grimberg <sagi@grimberg.me>
References: <20210708092755.15660-1-dwagner@suse.de>
 <20210708092755.15660-6-dwagner@suse.de>
From:   Hannes Reinecke <hare@suse.de>
Message-ID: <8edf09e2-52c1-5b96-6d45-ec210ffc33e1@suse.de>
Date:   Thu, 8 Jul 2021 12:14:11 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <20210708092755.15660-6-dwagner@suse.de>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 7/8/21 11:27 AM, Daniel Wagner wrote:
> nvme_wait_freeze_timeout() in nvme_fc_recreate_io_queues() needs to be
> paired with a nvme_start_freeze(). Without freezing first we will always
> timeout in nvme_wait_freeze_timeout().
> 
> Note there is a similiar fix for RDMA 9f98772ba307 ("nvme-rdma: fix
> controller reset hang during traffic") which happens to follow the PCI
> strategy how to handle resetting the queues.
> 
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>   drivers/nvme/host/fc.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 8e1fc3796735..a38b01485939 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -3249,6 +3249,7 @@ nvme_fc_delete_association(struct nvme_fc_ctrl *ctrl)
>   		nvme_fc_xmt_ls_rsp(disls);
>   
>   	if (ctrl->ctrl.tagset) {
> +		nvme_start_freeze(&ctrl->ctrl);
>   		nvme_fc_delete_hw_io_queues(ctrl);
>   		nvme_fc_free_io_queues(ctrl);
>   	}
> 
Please add a comment here about the pairing. We've missed it once, so we 
should make it clear why it has to be placed here.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer