Re: [PATCH v3] USB:UAS:return ENODEV when submit urbs fail with device not attached

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Mar 01, 2024 at 03:33:49AM +0800, Weitao Wang wrote:
> In the scenario of entering hibernation with udisk in the system, if the
> udisk was gone or resume fail in the thaw phase of hibernation. Its state
> will be set to NOTATTACHED. At this point, usb_hub_wq was already freezed
> and can't not handle disconnect event. Next, in the poweroff phase of
> hibernation, SYNCHRONIZE_CACHE SCSI command will be sent to this udisk
> when poweroff this scsi device, which will cause uas_submit_urbs to be
> called to submit URB for sense/data/cmd pipe. However, these URBs will
> submit fail as device was set to NOTATTACHED state. Then, uas_submit_urbs
> will return a value SCSI_MLQUEUE_DEVICE_BUSY to the caller. That will lead
> the SCSI layer go into an ugly loop and system fail to go into hibernation.
> 
> On the other hand, when we specially check for -ENODEV in function
> uas_queuecommand_lck, returning DID_ERROR to SCSI layer will cause device
> poweroff fail and system shutdown instead of entering hibernation.
> 
> To fix this issue, let uas_submit_urbs to return original generic error
> when submitting URB failed. At the same time, we need to translate -ENODEV
> to DID_NOT_CONNECT for the SCSI layer.
> 
> Suggested-by: Oliver Neukum <oneukum@suse.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
> ---
> v2->v3
>  - Modify the description of this patch.
>  - An error is returned directly when submitting URB fails.

This change breaks the build, please be more careful:

drivers/usb/storage/uas.c: In function ‘uas_submit_urbs’:
drivers/usb/storage/uas.c:559:21: error: unused variable ‘urb’ [-Werror=unused-variable]
  559 |         struct urb *urb;
      |                     ^~~


thanks,

greg k-h