Re: [PATCH 14/18] scsi_dh_alua: simplify sense code handling

[Johannes Thumshirn <jthumshirn@suse.com>]

On Tue, 2015-12-01 at 10:16 +0100, Hannes Reinecke wrote:
> Most sense code is already handled in the generic
> code, so we shouldn't be adding special cases here.
> However, when doing so we need to check for
> unit attention whenever we're sending an internal
> command.
> 
> Reviewed-by: Ewan Milne <emilne@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  drivers/scsi/device_handler/scsi_dh_alua.c | 45 +++++++++++-----------------
> --
>  1 file changed, 17 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c
> b/drivers/scsi/device_handler/scsi_dh_alua.c
> index c9751c9..abf05b4 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -85,7 +85,6 @@ struct alua_dh_data {
>  #define ALUA_POLICY_SWITCH_ALL		1
>  
>  static char print_alua_state(int);
> -static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
>  
>  static int realloc_buffer(struct alua_dh_data *h, unsigned len)
>  {
> @@ -189,8 +188,13 @@ static void stpg_endio(struct request *req, int error)
>  
>  	if (scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
>  				 &sense_hdr)) {
> -		err = alua_check_sense(h->sdev, &sense_hdr);
> -		if (err == ADD_TO_MLQUEUE) {
> +		if (sense_hdr.sense_key == NOT_READY &&
> +		    sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) {
> +			/* ALUA state transition already in progress */
> +			err = SCSI_DH_OK;
> +			goto done;
> +		}
> +		if (sense_hdr.sense_key == UNIT_ATTENTION) {
>  			err = SCSI_DH_RETRY;
>  			goto done;
>  		}
> @@ -399,28 +403,6 @@ static int alua_check_sense(struct scsi_device *sdev,
>  			 * LUN Not Accessible - ALUA state transition
>  			 */
>  			return ADD_TO_MLQUEUE;
> -		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
> -			/*
> -			 * LUN Not Accessible -- Target port in standby
> state
> -			 */
> -			return SUCCESS;
> -		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
> -			/*
> -			 * LUN Not Accessible -- Target port in unavailable
> state
> -			 */
> -			return SUCCESS;
> -		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
> -			/*
> -			 * LUN Not Ready -- Offline
> -			 */
> -			return SUCCESS;
> -		if (sdev->allow_restart &&
> -		    sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x02)
> -			/*
> -			 * if the device is not started, we need to wake
> -			 * the error handler to start the motor
> -			 */
> -			return FAILED;
>  		break;
>  	case UNIT_ATTENTION:
>  		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
> @@ -517,9 +499,16 @@ static int alua_rtpg(struct scsi_device *sdev, struct
> alua_dh_data *h, int wait_
>  			h->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
>  			goto retry;
>  		}
> -
> -		err = alua_check_sense(sdev, &sense_hdr);
> -		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) {
> +		/*
> +		 * Retry on ALUA state transition or if any
> +		 * UNIT ATTENTION occurred.
> +		 */
> +		if (sense_hdr.sense_key == NOT_READY &&
> +		    sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
> +			err = SCSI_DH_RETRY;
> +		else if (sense_hdr.sense_key == UNIT_ATTENTION)
> +			err = SCSI_DH_RETRY;
> +		if (err == SCSI_DH_RETRY && time_before(jiffies, expiry)) {
>  			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
>  				    ALUA_DH_NAME);
>  			scsi_print_sense_hdr(sdev, ALUA_DH_NAME,
> &sense_hdr);

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
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