[PATCH v2 0/2] scsi: ufs: core: Avoid redundant link recovery during system resume

[HOYOUNG SEO <hy50.seo@samsung.com>]

If a LINERESET is reported and the hibern8 exit fails during system
resume, both ufshcd_err_handler() and __ufshcd_wl_resume() call
ufshcd_link_recovery(), and the two recoveries are not serialized.

Patch 1 makes ufshcd_link_recovery() clear the saved errors like
ufshcd_reset_and_restore() does, so the error handler does not act on
errors that have already been recovered.

Patch 2 makes ufshcd_err_handler() wait for host_sem instead of
recovering the link early when the hba is system suspended.

Changes in v2:
- Add patch 1. As pointed out by the Sashiko review, saved_err and
  saved_uic_err are still set after the resume path recovered the link,
  so with v1 alone ufshcd_err_handler() would run a redundant recovery
  once host_sem is released.
- Patch 2: describe the race and the system/runtime PM difference in
  the commit message, and add a comment.

HOYOUNG SEO (2):
  scsi: ufs: core: Clear saved errors in ufshcd_link_recovery
  scsi: ufs: core: add is_sys_suspended state before recovery

 drivers/ufs/core/ufshcd.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

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2.34.1