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SubjectRe: [PATCH v5 06/15] scsi: ufs: avoid exception event handler racing with PM callbacks
From
Reviewed-by: Gilad Broner <gbroner@codeaurora.org>

> If device raises the exception event in the response to the commands
> sent during the runtime/system PM callbacks, exception event handler
> might run in parallel with PM callbacks and may see unclocked register
> accesses. This change fixes this issue by not scheduling the exception
> event handler while PM callbacks are running.
>
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
>
> ---
> drivers/scsi/ufs/ufshcd.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 573a8cb..0e54183 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -3145,7 +3145,20 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba,
> struct ufshcd_lrb *lrbp)
> scsi_status = result & MASK_SCSI_STATUS;
> result = ufshcd_scsi_cmd_status(lrbp, scsi_status);
>
> - if (ufshcd_is_exception_event(lrbp->ucd_rsp_ptr))
> + /*
> + * Currently we are only supporting BKOPs exception
> + * events hence we can ignore BKOPs exception event
> + * during power management callbacks. BKOPs exception
> + * event is not expected to be raised in runtime suspend
> + * callback as it allows the urgent bkops.
> + * During system suspend, we are anyway forcefully
> + * disabling the bkops and if urgent bkops is needed
> + * it will be enabled on system resume. Long term
> + * solution could be to abort the system suspend if
> + * UFS device needs urgent BKOPs.
> + */
> + if (!hba->pm_op_in_progress &&
> + ufshcd_is_exception_event(lrbp->ucd_rsp_ptr))
> schedule_work(&hba->eeh_work);
> break;
> case UPIU_TRANSACTION_REJECT_UPIU:
> --
> 1.8.5.2
>
> --
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> of Code Aurora Forum, hosted by The Linux Foundation
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--
Qualcomm Israel, on behalf of Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project



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