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Date:   Wed, 16 Jan 2019 15:52:15 +0100
From:   Roger Pau =?utf-8?B?TW9ubsOp?= <roger.pau@citrix.com>
To:     Dongli Zhang <dongli.zhang@oracle.com>
CC:     <xen-devel@lists.xenproject.org>, <linux-block@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <konrad.wilk@oracle.com>,
        <axboe@kernel.dk>
Subject: Re: [PATCH 1/1] xen-blkback: do not wake up shutdown_wq after
 xen_blkif_schedule() is stopped
Message-ID: <20190116145215.igakzdkklc6f7h6k@mac>
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On Wed, Jan 16, 2019 at 09:47:41PM +0800, Dongli Zhang wrote:
> There is no need to wake up xen_blkif_schedule() as kthread_stop() is able
> to already wake up the kernel thread.
> 
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
>  drivers/block/xen-blkback/xenbus.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
> index a4bc74e..37ac59e 100644
> --- a/drivers/block/xen-blkback/xenbus.c
> +++ b/drivers/block/xen-blkback/xenbus.c
> @@ -254,10 +254,8 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
>  		if (!ring->active)
>  			continue;
>  
> -		if (ring->xenblkd) {
> +		if (ring->xenblkd)
>  			kthread_stop(ring->xenblkd);
> -			wake_up(&ring->shutdown_wq);

I've now realized that shutdown_wq is basically useless, and should be
removed, could you please do it in this patch?

Thanks, Roger.