Re: [PATCH 1/1] scsi: ufs: fix exception event handling

[Subhash Jadavani]

On 2018-01-28 20:34, Asutosh Das wrote:
> From: Maya Erez <merez@xxxxxxxxxxxxxx>
>
> The device can set the exception event bit in one of the response UPIU,
> for example to notify the need for urgent BKOPs operation.
> In such a case the host driver calls ufshcd_exception_event_handler to
> handle this notification.
> When trying to check the exception event status (for finding the cause 
> for
> the exception event), the device may be busy with additional SCSI 
> commands
> handling and may not respond within the 100ms timeout.
>
> To prevent that, we need to block SCSI commands during handling of
> exception events and allow retransmissions of the query requests,
> in case of timeout.
>
> Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> Signed-off-by: Maya Erez <merez@xxxxxxxxxxxxxx>
> Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> ---
>  drivers/scsi/ufs/ufshcd.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 8af2af3..2dd488f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -4955,6 +4955,7 @@ static void
> ufshcd_exception_event_handler(struct work_struct *work)
>  	hba = container_of(work, struct ufs_hba, eeh_work);
>
>  	pm_runtime_get_sync(hba->dev);
> +	scsi_block_requests(hba->host);
>  	err = ufshcd_get_ee_status(hba, &status);
>  	if (err) {
>  		dev_err(hba->dev, "%s: failed to get exception status %d\n",
> @@ -4968,6 +4969,7 @@ static void
> ufshcd_exception_event_handler(struct work_struct *work)
>  		ufshcd_bkops_exception_event_handler(hba);
>
>  out:
> +	scsi_unblock_requests(hba->host);
>  	pm_runtime_put_sync(hba->dev);
>  	return;
>  }

Looks good to me.
Reviewed-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>

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