On 10/02/2015 02:07 AM, Bart Van Assche wrote:
> On 09/29/2015 03:47 AM, Hannes Reinecke wrote:
>> Seperate out SET TARGET PORT GROUP functionality into a separate
> ^ Separate ?
>> function alua_stpg().
>>
>> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
>> ---
>> drivers/scsi/device_handler/scsi_dh_alua.c | 86
>> ++++++++++++++++++------------
>> 1 file changed, 52 insertions(+), 34 deletions(-)
>>
>> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c
>> b/drivers/scsi/device_handler/scsi_dh_alua.c
>> index 63423b2..59fe3e9 100644
>> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
>> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
>> @@ -614,6 +614,56 @@ static int alua_rtpg(struct scsi_device
>> *sdev, struct alua_dh_data *h, int wait_
>> }
>>
>> /*
>> + * alua_stpg - Issue a SET TARGET GROUP STATES command
>> + *
>> + * Issue a SET TARGET GROUP STATES command and evaluate the
>> + * response. Returns SCSI_DH_RETRY per default to trigger
>> + * a re-evaluation of the target group state.
>> + */
>
> In SPC-4 I found the following description next to the STPG command:
> "SET TARGET PORT GROUPS". How about using the official SPC-4
> description ?
>
>> +static unsigned alua_stpg(struct scsi_device *sdev, struct
>> alua_dh_data *h,
>> + activate_complete fn, void *data)
>> +{
>> + int err = SCSI_DH_OK;
>> + int stpg = 0;
>> +
>> + if (!(h->tpgs & TPGS_MODE_EXPLICIT)) {
>> + /* Only implicit ALUA supported */
>> + return err;
>> + }
>> +
>> + switch (h->state) {
>> + case TPGS_STATE_NONOPTIMIZED:
>> + stpg = 1;
>> + if ((h->flags & ALUA_OPTIMIZE_STPG) &&
>> + !h->pref &&
>> + (h->tpgs & TPGS_MODE_IMPLICIT))
>> + stpg = 0;
>> + break;
>> + case TPGS_STATE_STANDBY:
>> + case TPGS_STATE_UNAVAILABLE:
>> + stpg = 1;
>> + break;
>> + case TPGS_STATE_OFFLINE:
>> + err = SCSI_DH_IO;
>> + break;
>> + case TPGS_STATE_TRANSITIONING:
>> + err = SCSI_DH_RETRY;
>> + break;
>> + default:
>> + break;
>> + }
>> +
>> + if (stpg) {
>> + h->callback_fn = fn;
>> + h->callback_data = data;
>> + err = submit_stpg(h);
>> + if (err != SCSI_DH_OK)
>> + h->callback_fn = h->callback_data = NULL;
>> + }
>> + return err;
>> +}
>> +
>> +/*
>> * alua_initialize - Initialize ALUA state
>> * @sdev: the device to be initialized
>> *
>> @@ -690,7 +740,6 @@ static int alua_activate(struct scsi_device
>> *sdev,
>> {
>> struct alua_dh_data *h = sdev->handler_data;
>> int err = SCSI_DH_OK;
>> - int stpg = 0;
>>
>> err = alua_rtpg(sdev, h, 1);
>> if (err != SCSI_DH_OK)
>> @@ -699,41 +748,10 @@ static int alua_activate(struct scsi_device
>> *sdev,
>> if (optimize_stpg)
>> h->flags |= ALUA_OPTIMIZE_STPG;
>>
>> - if (h->tpgs & TPGS_MODE_EXPLICIT) {
>> - switch (h->state) {
>> - case TPGS_STATE_NONOPTIMIZED:
>> - stpg = 1;
>> - if ((h->flags & ALUA_OPTIMIZE_STPG) &&
>> - (!h->pref) &&
>> - (h->tpgs & TPGS_MODE_IMPLICIT))
>> - stpg = 0;
>> - break;
>> - case TPGS_STATE_STANDBY:
>> - case TPGS_STATE_UNAVAILABLE:
>> - stpg = 1;
>> - break;
>> - case TPGS_STATE_OFFLINE:
>> - err = SCSI_DH_IO;
>> - break;
>> - case TPGS_STATE_TRANSITIONING:
>> - err = SCSI_DH_RETRY;
>> - break;
>> - default:
>> - break;
>> - }
>> - }
>> -
>> - if (stpg) {
>> - h->callback_fn = fn;
>> - h->callback_data = data;
>> - err = submit_stpg(h);
>> - if (err == SCSI_DH_OK)
>> - return 0;
>> - h->callback_fn = h->callback_data = NULL;
>> - }
>> + err = alua_stpg(sdev, h, fn, data);
>>
>> out:
>> - if (fn)
>> + if (err != SCSI_DH_OK && fn)
>> fn(data, err);
>> return 0;
>> }
>>
>
> The old implementation calls the callback function 'fn' if the flag
> TPGS_MODE_EXPLICIT has not been set but the new implementation not.
> Please mention this in the patch description if this behavior change
> is intentional.
>
Actually, this looks more like an error with the old implementation.
'fn' is the callback signalling that the failover command has been
completed, and the caller (in most case dm-multipath) relies on 'fn'
to be executed for further processing.
So 'fn' should be executed, irrespective of the TPGS_MODE_EXPLICIT flag.
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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