Re: [PATCH v8 3/3] scsi: ufs: core: Limit early link recovery in the error handler to runtime PM

[Peter Wang <peter.wang@mediatek.com>]

On Mon, 2026-11-09 at 13:09 +0900, HOYOUNG SEO wrote:
> ufshcd_err_handler() recovers the link without taking hba->host_sem
> whenever hba->pm_op_in_progress is set. That early path was added by
> commit f966e02ae521 ("scsi: ufs: core: Fix runtime suspend error
> deadlock") because the regular error handling would wait for a
> runtime
> PM operation that cannot complete while the error handler is waiting.
> 
> pm_op_in_progress is also set during system suspend, system resume,
> shutdown and poweroff, where the early path is not needed and runs
> concurrently with the PM path itself. For example, if a LINERESET is
> reported and the hibern8 exit fails in __ufshcd_wl_resume() during
> system resume, both ufshcd_err_handler() and __ufshcd_wl_resume()
> call
> ufshcd_link_recovery(), and the host and the device may be reset at
> the
> same time.
> 
> Only take the early path while a runtime suspend or resume of the
> WLUN
> is in progress. The runtime PM core sets the runtime status of the
> WLUN
> to RPM_SUSPENDING or RPM_RESUMING while ufshcd_wl_runtime_suspend()
> or
> ufshcd_wl_runtime_resume() runs, and it is RPM_ACTIVE or
> RPM_SUSPENDED
> during system PM. Read it with READ_ONCE() without power.lock held in
> the new helper ufshcd_rpm_transition_in_progress(), next to the other
> ufshcd_rpm_*() helpers. The status is only available with CONFIG_PM,
> so
> the helper returns false without it.
> 
> For the other PM operations the regular error handling is safe:
> 
>   - the system PM callbacks hold host_sem from ufshcd_wl_suspend()
> until
>     ufshcd_wl_resume() returns, and ufshcd_wl_poweroff() holds it as
>     well, so the error handler waits for them;
>   - during shutdown, hba->shutting_down makes the error handler stop.
> 
> This changes the behavior during shutdown: errors that occur while
> the
> final START STOP UNIT command is being processed are no longer
> handled
> by the error handler. Recovery then only happens through
> ufshcd_eh_timed_out().
> 
> Fixes: e23ef4f22db3 ("scsi: ufs: core: Fix error handler host_sem
> issue")
> Signed-off-by: HOYOUNG SEO <hy50.seo@samsung.com>
> ---

Sashiko report issue is previous issue and should be 
fixed separately.

Reviewed-by: Peter Wang <peter.wang@mediatek.com>