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Date:   Fri, 13 Aug 2021 09:44:00 +0800
From:   wat@codeaurora.org
To:     Mathias Nyman <mathias.nyman@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     quic_wat@quicinc.com, wat@codeaurora.org
Subject: Re: [PATCH] usb: xhci-ring: USB SSD may fail to unmount if disconnect
 during data transferring.
In-Reply-To: <1628769727-45046-1-git-send-email-wat@codeaurora.org>
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Message-ID: <83812530fbe1ba6f93c0978019bf118b@codeaurora.org>
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Hi usb teams,

I have a patch about xhci-ring, can you help me to check?

you can contact me if you have any question.


On 2021-08-12 20:02, Tao Wang wrote:
> From: Tao Wang <quic_wat@quicinc.com>
> 
> it stuck in usb_kill_urb() due to urb use_count will not become zero,
> this means urb giveback is not happen.
> in xhci_handle_cmd_set_deq() will giveback urb if td's cancel_status
> equal to TD_CLEARING_CACHE,
> but in xhci_invalidate_cancelled_tds(), only last canceled td's
> cancel_status change to TD_CLEARING_CACHE,
> thus giveback only happen to last urb.
> 
> this change set all cancelled_td's cancel_status to TD_CLEARING_CACHE
> rather than the last one, so all urb can giveback.
> 
> Signed-off-by: Tao Wang <quic_wat@quicinc.com>
> ---
>  drivers/usb/host/xhci-ring.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-ring.c 
> b/drivers/usb/host/xhci-ring.c
> index 8fea44b..c7dd7c0 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -960,19 +960,19 @@ static int xhci_invalidate_cancelled_tds(struct
> xhci_virt_ep *ep)
>  			td_to_noop(xhci, ring, td, false);
>  			td->cancel_status = TD_CLEARED;
>  		}
> -	}
> -	if (cached_td) {
> -		cached_td->cancel_status = TD_CLEARING_CACHE;
> -
> -		err = xhci_move_dequeue_past_td(xhci, slot_id, ep->ep_index,
> -						cached_td->urb->stream_id,
> -						cached_td);
> -		/* Failed to move past cached td, try just setting it noop */
> -		if (err) {
> -			td_to_noop(xhci, ring, cached_td, false);
> -			cached_td->cancel_status = TD_CLEARED;
> +		if (cached_td) {
> +			cached_td->cancel_status = TD_CLEARING_CACHE;
> +
> +			err = xhci_move_dequeue_past_td(xhci, slot_id, ep->ep_index,
> +							cached_td->urb->stream_id,
> +							cached_td);
> +			/* Failed to move past cached td, try just setting it noop */
> +			if (err) {
> +				td_to_noop(xhci, ring, cached_td, false);
> +				cached_td->cancel_status = TD_CLEARED;
> +			}
> +			cached_td = NULL;
>  		}
> -		cached_td = NULL;
>  	}
>  	return 0;
>  }