From mboxrd@z Thu Jan  1 00:00:00 1970
From: bvanassche@acm.org (Bart Van Assche)
Date: Mon, 22 Jul 2019 08:27:32 -0700
Subject: [PATCH 3/5] nvme: don't abort completed request in
 nvme_cancel_request
In-Reply-To: <20190722053954.25423-4-ming.lei@redhat.com>
References: <20190722053954.25423-1-ming.lei@redhat.com>
 <20190722053954.25423-4-ming.lei@redhat.com>
Message-ID: <d82ead02-c893-4d14-307e-70a6d4596439@acm.org>

On 7/21/19 10:39 PM, Ming Lei wrote:
> Before aborting in-flight requests, all IO queues have been shutdown.
> However, request's completion fn may not be done yet because it may
> be scheduled to run via IPI.
> 
> So don't abort one request if it is marked as completed, otherwise
> we may abort one normal completed request.
> 
> Cc: Max Gurtovoy <maxg at mellanox.com>
> Cc: Sagi Grimberg <sagi at grimberg.me>
> Cc: Keith Busch <keith.busch at intel.com>
> Cc: Christoph Hellwig <hch at lst.de>
> Signed-off-by: Ming Lei <ming.lei at redhat.com>
> ---
>   drivers/nvme/host/core.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index cc09b81fc7f4..cb8007cce4d1 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -285,6 +285,10 @@ EXPORT_SYMBOL_GPL(nvme_complete_rq);
>   
>   bool nvme_cancel_request(struct request *req, void *data, bool reserved)
>   {
> +	/* don't abort one completed request */
> +	if (blk_mq_request_completed(req))
> +		return;
> +
>   	dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
>   				"Cancelling I/O %d", req->tag);

Something I probably already asked before: what prevents that 
nvme_cancel_request() is executed concurrently with the completion 
handler of the same request?

Thanks,

Bart.