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(-)
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