[RFC PATCH v3 0/1] Enable power management for ufs wlun

[Asutosh Das <asutoshd@codeaurora.org>]

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

I'm testing it out now, please take a look and let me know.

Asutosh Das (1):
  scsi: ufs: Enable power management for wlun

 drivers/scsi/ufs/ufshcd.c  | 415 +++++++++++++++++++++++++++++++++++++--------
 drivers/scsi/ufs/ufshcd.h  |   4 +
 include/trace/events/ufs.h |  20 +++
 3 files changed, 364 insertions(+), 75 deletions(-)

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