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

["WeitaoWang-oc@zhaoxin.com" <WeitaoWang-oc@zhaoxin.com>]

On 2024/3/5 21:25, Greg KH wrote:
> 
> 
> 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;
>       |                     ^~~
> 

I'm sorry for the carelessness. Now, I have removed this unused variable
and completed the compilation test. I'll resubmit this patch with a new version.

Thanks
weitao