On 15/09/21 1:28 am, Bart Van Assche wrote:
> On 9/13/21 9:55 PM, Adrian Hunter wrote:
>> On 13/09/21 11:11 pm, Bart Van Assche wrote: >> What am I missing?
>>
>> You have not responded to the issues raised by
>> "scsi: ufs: Synchronize SCSI and UFS error handling"
>
> Because one of the follow-up messages to that patch was so cryptic that I
> did not comprehend it. Anyway, based on the patch at the start of this email
> thread I assume that the deadlock is caused by calling blk_get_request()
> without the BLK_MQ_REQ_NOWAIT flag from inside a SCSI error handler. How
> about fixing this by removing the code that submits a REQUEST SENSE command
> and calling scsi_report_bus_reset() or scsi_report_device_reset() instead?
> ufshcd_reset_and_restore() already uses that approach to make sure that the
> unit attention condition triggered by a reset is not reported to the SCSI
> command submitter. I think only if needs_restore == true and
> needs_reset == false that ufshcd_err_handler() can trigger a UA condition
> without calling scsi_report_bus_reset().
>
> The following code from scsi_error.c makes sure that the UA after a reset
> does not reach the upper-level driver:
>
> case NOT_READY:
> case UNIT_ATTENTION:
> /*
> * if we are expecting a cc/ua because of a bus reset that we
> * performed, treat this just as a retry. otherwise this is
> * information that we should pass up to the upper-level driver
> * so that we can deal with it there.
> */
> if (scmd->device->expecting_cc_ua) {
> /*
> * Because some device does not queue unit
> * attentions correctly, we carefully check
> * additional sense code and qualifier so as
> * not to squash media change unit attention.
> */
> if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
> scmd->device->expecting_cc_ua = 0;
> return NEEDS_RETRY;
> }
> }
>
> Bart.
Thanks for the idea. Unfortunately it does not work for pass-through
requests, refer scsi_noretry_cmd(). sdev_ufs_device and sdev_rpmb are
used with pass-through requests.
