On 09/22/2015 09:10 PM, Ewan Milne wrote:
> On Thu, 2015-08-27 at 14:41 +0200, 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: Christoph Hellwig <hch@xxxxxx>
>> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
>> ---
>> drivers/scsi/device_handler/scsi_dh_alua.c | 50 +++++++-----------------------
>> 1 file changed, 11 insertions(+), 39 deletions(-)
>>
>> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
>> index 4157fe2..dbe9ff2 100644
>> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
>> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
>> @@ -91,7 +91,6 @@ 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 void release_port_group(struct kref *kref)
>> {
>> @@ -323,28 +322,6 @@ 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)
>> @@ -359,7 +336,7 @@ static int alua_check_sense(struct scsi_device *sdev,
>> return ADD_TO_MLQUEUE;
>> if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
>> /*
>> - * Mode Parameters Changed
>> + * Mode Parameter Changed
>
> See below.
>
>> */
>> return ADD_TO_MLQUEUE;
>> if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
>> @@ -372,18 +349,6 @@ static int alua_check_sense(struct scsi_device *sdev,
>> * Implicit ALUA state transition failed
>> */
>> return ADD_TO_MLQUEUE;
>> - if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
>> - /*
>> - * Inquiry data has changed
>> - */
>> - return ADD_TO_MLQUEUE;
>
> ??? See below.
>
>> - if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
>> - /*
>> - * REPORTED_LUNS_DATA_HAS_CHANGED is reported
>> - * when switching controllers on targets like
>> - * Intel Multi-Flex. We can just retry.
>> - */
>> - return ADD_TO_MLQUEUE;
>
> ??? See below.
>
>> break;
>> }
>>
>> @@ -448,9 +413,16 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int w
>> pg->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);
>
> "Mode Parameters Changed" comment should not have been changed to "Mode Parameter Changed".
> The actual T10 text is "Mode Parameters Changed", so leave it the way it is.
>
Okay.
> The sense code handling in the UA case for ASC/ASCQ 3F 03 is changed by this patch to
> return SUCCESS from scsi_check_sense() instead of ADD_TO_MLQUEUE from alua_check_sense(),
> and the sense code handling in the UA case for ASC/ASCQ 3F 0E is changed by this patch to
> return NEEDS_RETRY from scsi_check_sense() instead of ADD_TO_MLQUEUE from alua_check_sense().
> So we will not reissue the command on INQUIRY DATA HAS CHANGED and will have different
> flow of control on REPORTED LUNS DATA HAS CHANGED. What is the reason for this?
>
'INQUIRY DATA HAS CHANGED' will be handled with a later patch, so I
had it removed from here. But indeed, these hunks shouldn't be
removed. I'll be reverting that.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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