[PATCH v9 0/9] Fix up and simplify error recovery mechanism

[Can Guo <cang@codeaurora.org>]

The changes have been tested with error injections of multiple error types (and
all kinds of mixture of them) during runtime, e.g. hibern8 enter/ exit error,
power mode change error and fatal/non-fatal error from IRQ context. During the
test, error injections happen randomly across all contexts, e.g. clk scaling,
clk gate/ungate, runtime suspend/resume and IRQ.

There are a few more fixes to resolve other minor problems based on the main
change, such as LINERESET handling and racing btw error handler and system
suspend/resume/shutdown, but they will be pushed after this series is taken,
due to there are already too many lines in these changes.

Change since v8:
- Added one more fix to ufshcd_abort as requested by Stanley Chu

Change since v7:
- Incorporated Asutosh's comments
- Refined patch "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v6:
- Modified change "scsi: ufs-qcom: Fix schedule while atomic error in ufs_qcom_dump_dbg_regs" to "scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs"

Change since v5:
- Dropped change "scsi: ufs: Fix imbalanced scsi_block_reqs_cnt caused by ufshcd_hold()" as it is not quite related with this series
- Refined func ufshcd_err_handling_prepare in change "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v4:
- Split the original change "ufs: ufs-qcom: Fix a few BUGs in func ufs_qcom_dump_dbg_regs()" to 2 small changes

Change since v3:
- Split the original change "scsi: ufs: Fix up and simplify error recovery mechanism" into 5 changes

Change since v2:
- Incorporate Bart's comment to change "scsi: ufs: Add checks before setting clk-gating states"
- Revised the commit msg of change "scsi: ufs: Fix up and simplify error recovery mechanism"

Change since v1:
- Fixed a compilation error in case that CONFIG_PM is N

Can Guo (9):
  scsi: ufs: Add checks before setting clk-gating states
  ufs: ufs-qcom: Fix race conditions caused by func
    ufs_qcom_testbus_config
  scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs
  scsi: ufs: Add some debug infos to ufshcd_print_host_state
  scsi: ufs: Fix concurrency of error handler and other error recovery
    paths
  scsi: ufs: Recover hba runtime PM error in error handler
  scsi: ufs: Move dumps in IRQ handler to error handler
  scsi: ufs: Fix a racing problem btw error handler and runtime PM ops
  scsi: ufs: Properly release resources if a task is aborted
    successfully

 drivers/scsi/ufs/ufs-qcom.c  |  37 ----
 drivers/scsi/ufs/ufs-sysfs.c |   1 +
 drivers/scsi/ufs/ufshcd.c    | 508 +++++++++++++++++++++++++++----------------
 drivers/scsi/ufs/ufshcd.h    |  14 ++
 4 files changed, 338 insertions(+), 222 deletions(-)

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