[PATCH v1 0/2] scsi: ufs: Fix broken hba->outstanding_tasks

[Stanley Chu <stanley.chu@mediatek.com>]

Currently bits in hba->outstanding_tasks are cleared only after their
corresponding task management commands are successfully done by
__ufshcd_issue_tm_cmd().

If timeout happens in a task management command, its corresponding
bit in hba->outstanding_tasks will not be cleared until next task
management command with the same tag used successfully finishes.‧

This is wrong and can lead to some issues, like power consumpton issue.
For example, ufshcd_release() and ufshcd_gate_work() will do nothing
if hba->outstanding_tasks is not zero even if both UFS host and devices
are actually idle.

Because error handling flow, i.e., ufshcd_reset_and_restore(), will be
triggered after any task management command times out, we fix this by
clearing corresponding hba->outstanding_tasks bits during this flow.
To achieve this, we need a mask to track timed-out commands and thus
error handling flow can clear their tags specifically.

Stanley Chu (2):
  scsi: ufs: Make new function for clearing outstanding task bits
  scsi: ufs: Fix broken hba->outstanding_tasks

 drivers/scsi/ufs/ufshcd.c | 49 +++++++++++++++++++++++++++++++++------
 drivers/scsi/ufs/ufshcd.h |  1 +
 2 files changed, 43 insertions(+), 7 deletions(-)

-- 
2.18.0


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