Re: [PATCH V2] scsi: ufs: core: Fix synchronization between scsi_unjam_host() and ufshcd_queuecommand()

["Asutosh Das (asd)" <asutoshd@codeaurora.org>]

On 10/8/2021 1:40 AM, Adrian Hunter wrote:
> The SCSI error handler calls scsi_unjam_host() which can call the queue
> function ufshcd_queuecommand() indirectly. The error handler changes the
> state to UFSHCD_STATE_RESET while running, but error interrupts that
> happen while the error handler is running could change the state to
> UFSHCD_STATE_EH_SCHEDULED_NON_FATAL which would allow requests to go
> through ufshcd_queuecommand() even though the error handler is running.
> Block that hole by checking whether the error handler is in progress.
> 
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---

LGTM.
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>

> 
> Changes in V2:
> 
> 	Add comment
> 
>   drivers/scsi/ufs/ufshcd.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index f34227add27d..29d202207b18 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -2688,7 +2688,19 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
>   
>   	switch (hba->ufshcd_state) {
>   	case UFSHCD_STATE_OPERATIONAL:
> +		break;
>   	case UFSHCD_STATE_EH_SCHEDULED_NON_FATAL:
> +		/*
> +		 * SCSI error handler can call ->queuecommand() while UFS error
> +		 * handler is in progress. Error interrupts could change the
> +		 * state from UFSHCD_STATE_RESET to
> +		 * UFSHCD_STATE_EH_SCHEDULED_NON_FATAL. Prevent requests
> +		 * being issued in that case.
> +		 */
> +		if (ufshcd_eh_in_progress(hba)) {
> +			err = SCSI_MLQUEUE_HOST_BUSY;
> +			goto out;
> +		}
>   		break;
>   	case UFSHCD_STATE_EH_SCHEDULED_FATAL:
>   		/*
> 


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