On 3/24/2021 6:39 PM, Asutosh Das wrote:

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

v12 -> v13:
- Addressed Adrian's comments
   * Paired pm_runtime_get_noresume() with pm_runtime_put()
   * no rpm_autosuspend for ufs device wlun
   * Moved runtime-pm init functionality to ufshcd_wl_probe()
- Addressed Bart's comments
   * Expanded abbrevs in commit message

Hi Adrian
I did a limited testing on your fix in the pm framework along with this 
v13 patchset. I couldn't reproduce the issue.

I'd appreciate if you can please take a look at the v13 changes.
If all looks good in that, I'd do an extensive testing.

Thanks,
-asd

v11 -> v12:
- Addressed Adrian's comments
   * Fixed ahit for Mediatek driver
   * Fixed error handling in ufshcd_core_init()
   * Tested this patch and the issue is still seen.

v10 -> v11:
- Fixed supplier suspending before consumer race
- Addressed Adrian's comments
   * Added proper resume/suspend cb to ufshcd_auto_hibern8_update()
   * Cosmetic changes to ufshcd-pci.c
   * Cleaned up ufshcd_system_suspend()
   * Added ufshcd_debugfs_eh_exit to ufshcd_core_init()

v9 -> v10:
- Addressed Adrian's comments
   * Moved suspend/resume vops to __ufshcd_wl_[suspend/resume]()
   * Added correct resume in ufs_bsg

v8 -> v9:
- Addressed Adrian's comments
   * Moved link transition to __ufshcd_wl_[suspend/resume]()
   * Fixed the other minor comments

v7 -> v8:
- Addressed Adrian's comments
   * Removed separate autosuspend delay for ufs-device lun
   * Fixed the ee handler getting scheduled during pm
   * Always runtime resume in suspend_prepare()
   * Added CONFIG_PM_SLEEP where needed
   
v6 -> v7:
   * Resume the ufs device before shutting it down

v5 -> v6:
- Addressed Adrian's comments
   * Added complete() cb
   * Added suspend_prepare() and complete() to all drivers
   * Moved suspend_prepare() and complete() to ufshcd
   * .poweroff() uses ufhcd_wl_poweroff()
   * Removed several forward declarations
   * Moved scsi_register_driver() to ufshcd_core_init()

v4 -> v5:
- Addressed Adrian's comments
   * Used the rpmb driver contributed by Adrian
   * Runtime-resume the ufs device during suspend to honor spm-lvl
   * Unregister the scsi_driver in ufshcd_remove()
   * Currently shutdown() puts the ufs device to power-down mode
     so, just removed ufshcd_pci_poweroff()
   * Quiesce the scsi device during shutdown instead of remove

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/cdns-pltfrm.c     |   2 +
  drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
  drivers/scsi/ufs/ufs-debugfs.c     |   2 +-
  drivers/scsi/ufs/ufs-debugfs.h     |   2 +-
  drivers/scsi/ufs/ufs-exynos.c      |   2 +
  drivers/scsi/ufs/ufs-hisi.c        |   2 +
  drivers/scsi/ufs/ufs-mediatek.c    |  12 +-
  drivers/scsi/ufs/ufs-qcom.c        |   2 +
  drivers/scsi/ufs/ufs-sysfs.c       |  30 +-
  drivers/scsi/ufs/ufs_bsg.c         |   6 +-
  drivers/scsi/ufs/ufshcd-pci.c      |  36 +--
  drivers/scsi/ufs/ufshcd.c          | 627 ++++++++++++++++++++++++++-----------
  drivers/scsi/ufs/ufshcd.h          |   6 +
  include/trace/events/ufs.h         |  20 ++
  14 files changed, 513 insertions(+), 238 deletions(-)

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