On Wed, 2021-07-21 at 20:34 -0700, Bart Van Assche wrote:

Clearing a unit attention synchronously from inside the UFS error
handler
may trigger the following deadlock:
- ufshcd_err_handler() calls ufshcd_err_handling_unprepare() and the
latter
  function calls ufshcd_clear_ua_wluns().
- ufshcd_clear_ua_wluns() submits a REQUEST SENSE command and that
command
  activates the SCSI error handler.
- The SCSI error handler calls ufshcd_host_reset_and_restore().
- ufshcd_host_reset_and_restore() executes the following code:
  ufshcd_schedule_eh_work(hba);
  flush_work(&hba->eh_work);

This sequence results in a deadlock (circular wait). Fix this by
requesting
sense data asynchronously.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Stanley Chu <redacted>
Cc: Can Guo <redacted>
Cc: Asutosh Das <redacted>
Cc: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Reviewed-by: Bean Huo <redacted>