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Date:   Thu, 16 Sep 2021 16:23:40 +0800
From:   Ming Lei <ming.lei@redhat.com>
To:     pkalever@redhat.com
Cc:     linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        nbd@other.debian.org, josef@toxicpanda.com, axboe@kernel.dk,
        idryomov@redhat.com, xiubli@redhat.com,
        Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Subject: Re: [PATCH v1 2/2] nbd: reset the queue/io_timeout to default on
 disconnect
Message-ID: <YUL/DGZiUnQQGHVX@T590>
References: <20210806142914.70556-1-pkalever@redhat.com>
 <20210806142914.70556-3-pkalever@redhat.com>
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On Fri, Aug 06, 2021 at 07:59:14PM +0530, pkalever@redhat.com wrote:
> From: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
> 
> Without any changes to NBD_ATTR_TIMEOUT (default is 30 secs),
> $ rbd-nbd map rbd-pool/image0 --try-netlink
> /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 30000
> $ rbd-nbd unmap /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 30000
> 
> Now user sets NBD_ATTR_TIMEOUT to 60,
> $ rbd-nbd map rbd-pool/image0 --try-netlink --io-timeout 60
> /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 60000
> $ rbd-nbd unmap /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 60000
> 
> Now user doesn't alter NBD_ATTR_TIMEOUT, but sysfs still shows it as 60,
> $ rbd-nbd map rbd-pool/image0 --try-netlink
> /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 60000
> $ rbd-nbd unmap /dev/nbd0
> $ cat /sys/block/nbd0/queue/io_timeout
> 60000
> 
> The problem exists with ioctl interface too.
> 
> Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
> ---
>  drivers/block/nbd.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 16a1a14b1fd1..a45aabc4914b 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -158,6 +158,7 @@ static void nbd_connect_reply(struct genl_info *info, int index);
>  static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
>  static void nbd_dead_link_work(struct work_struct *work);
>  static void nbd_disconnect_and_put(struct nbd_device *nbd);
> +static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout);
>  
>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>  {
> @@ -1250,7 +1251,7 @@ static void nbd_config_put(struct nbd_device *nbd)
>  			destroy_workqueue(nbd->recv_workq);
>  		nbd->recv_workq = NULL;
>  
> -		nbd->tag_set.timeout = 0;
> +		nbd_set_cmd_timeout(nbd, 0);
>  		nbd->disk->queue->limits.discard_granularity = 0;
>  		nbd->disk->queue->limits.discard_alignment = 0;
>  		blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
> @@ -2124,6 +2125,10 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
>  	if (ret)
>  		goto out;
>  
> +	/*
> +	 * On reconfigure, if NBD_ATTR_TIMEOUT is not provided, we will
> +	 * continue to use the cmd timeout provided with connect initially.
> +	 */
>  	if (info->attrs[NBD_ATTR_TIMEOUT])
>  		nbd_set_cmd_timeout(nbd,
>  				    nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
> -- 
> 2.31.1
> 

Looks fine:

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming