[v4,0/2] Enable power management for ufs wlun

Message

Asutosh Das (asd) Feb. 22, 2021, 11:04 p.m. UTC

This patch attempts to fix a deadlock in ufs while sending SSU.
Recently, blk_queue_enter() added a check to not process requests if the
queue is suspended. That leads to a resume of the associated device which
is suspended. In ufs, that device is ufs device wlun and it's parent is
ufs_hba. This resume tries to resume ufs device wlun which in turn tries
to resume ufs_hba, which is already in the process of suspending, thus
causing a deadlock.

This patch takes care of:
* Suspending the ufs device lun only after all other luns are suspended
* Sending SSU during ufs device wlun suspend
* Clearing uac for rpmb and ufs device wlun
* Not sending commands to the device during host suspend

v3 RFC -> v4:
- Addressed Bart's comments
  * Except that I didn't get any checkpatch failures
- Addressed Avri's comments
- Addressed Adrian's comments
  * Added a check for deepsleep power mode
  * Removed a couple of forward declarations
  * Didn't separate the scsi drivers because in rpmb case it just sends uac
    in resume and it seemed pretty neat to me.
- Added sysfs changes to resume the devices before accessing

Asutosh Das (2):
  scsi: ufs: Enable power management for wlun
  ufs: sysfs: Resume the proper scsi device

 drivers/scsi/ufs/ufs-sysfs.c |  26 +--
 drivers/scsi/ufs/ufshcd.c    | 455 ++++++++++++++++++++++++++++++++++---------
 drivers/scsi/ufs/ufshcd.h    |   4 +
 include/trace/events/ufs.h   |  20 ++
 4 files changed, 397 insertions(+), 108 deletions(-)