linux-kernel - Re: [PATCH v2 3/3] dmaengine: ioat: adding missed issue

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Message-ID: <f84bff8c-7cab-7c29-1a9a-6713a9a9cbf7@intel.com>
Date:   Wed, 22 Apr 2020 12:58:21 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     leonid.ravich@...l.com, dmaengine@...r.kernel.org
Cc:     lravich@...il.com, Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Alexander.Barabash@...l.com" <Alexander.Barabash@...l.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] dmaengine: ioat: adding missed issue_pending to
 timeout handler



On 4/22/2020 12:25 PM, leonid.ravich@...l.com wrote:
> From: Leonid Ravich <Leonid.Ravich@....com>
> 
> completion timeout might trigger unnesesery DMA engine hw reboot
> in case of missed issue_pending() .
> 
> Acked-by: Dave Jiang <dave.jiang@...el.com>
> Signed-off-by: Leonid Ravich <Leonid.Ravich@....com>
> ---
> Changing in v2
>    - add log in case of such scenario
>   drivers/dma/ioat/dma.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
> index 55a8cf1..a958aaf 100644
> --- a/drivers/dma/ioat/dma.c
> +++ b/drivers/dma/ioat/dma.c
> @@ -955,6 +955,14 @@ void ioat_timer_event(struct timer_list *t)
>   		goto unlock_out;
>   	}
>   
> +	/* handle missed issue pending case */
> +	if (ioat_ring_pending(ioat_chan)) {
> +		dev_dbg(to_dev(ioat_chan), "Complition timeout while pending\n")
Completion timeout with pending descriptors.

Also, maybe dev_warn() you think?

> +		spin_lock_bh(&ioat_chan->prep_lock);
> +		__ioat_issue_pending(ioat_chan);
> +		spin_unlock_bh(&ioat_chan->prep_lock);
> +	}
> +
>   	set_bit(IOAT_COMPLETION_ACK, &ioat_chan->state);
>   	mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
>   unlock_out:
>