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Re: [dm-devel] [PATCH] Use WWID from C8 page instead of Subsystem id from C4 page to identify storage



Looks good..

> -----Original Message-----
> From: Chandra Seetharaman [mailto:sekharan us ibm com]
> Sent: Wednesday, July 20, 2011 4:19 PM
> To: Linux SCSI Mailing list
> Cc: device-mapper development; Moger, Babu; Qi, Yanling; Stankey, Robert
> Subject: [PATCH] Use WWID from C8 page instead of Subsystem id from C4
> page to identify storage
> 
> rdac hardware handler uses "Subsystem Identifier" from C4 inquiry page
> to uniquely identify a storage. The problem with that is that if any
> any of the bytes are non-ascii, subsys_id will all be spaces (hex
> 0x20). This creates lot of problems especially when there are multiple
> rdac storages are connected to the server.
> 
> Use "Storage Array Unique Identifier" from C8 inquiry page, which is the
> world wide unique identifier for the storage array, to uniquely identify
> the storage.
> 
> Signed-off-by: Chandra Seetharaman <sekharan us ibm com>


Reviewed-by: Babu Moger <babu moger netapp com>

> ---
> diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c
> b/drivers/scsi/device_handler/scsi_dh_rdac.c
> index e7fc70d..a5d1669 100644
> --- a/drivers/scsi/device_handler/scsi_dh_rdac.c
> +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
> @@ -128,25 +128,7 @@ struct c4_inquiry {
>  	u8	reserved[2];
>  };
> 
> -struct rdac_controller {
> -	u8			subsys_id[SUBSYS_ID_LEN];
> -	u8			slot_id[SLOT_ID_LEN];
> -	int			use_ms10;
> -	struct kref		kref;
> -	struct list_head	node; /* list of all controllers */
> -	union			{
> -		struct rdac_pg_legacy legacy;
> -		struct rdac_pg_expanded expanded;
> -	} mode_select;
> -	u8	index;
> -	u8	array_name[ARRAY_LABEL_LEN];
> -	spinlock_t		ms_lock;
> -	int			ms_queued;
> -	struct work_struct	ms_work;
> -	struct scsi_device	*ms_sdev;
> -	struct list_head	ms_head;
> -};
> -
> +#define UNIQUE_ID_LEN 16
>  struct c8_inquiry {
>  	u8	peripheral_info;
>  	u8	page_code; /* 0xC8 */
> @@ -159,12 +141,30 @@ struct c8_inquiry {
>  	u8	vol_user_label_len;
>  	u8	vol_user_label[60];
>  	u8	array_uniq_id_len;
> -	u8	array_unique_id[16];
> +	u8	array_unique_id[UNIQUE_ID_LEN];
>  	u8	array_user_label_len;
>  	u8	array_user_label[60];
>  	u8	lun[8];
>  };
> 
> +struct rdac_controller {
> +	u8			array_id[UNIQUE_ID_LEN];
> +	int			use_ms10;
> +	struct kref		kref;
> +	struct list_head	node; /* list of all controllers */
> +	union			{
> +		struct rdac_pg_legacy legacy;
> +		struct rdac_pg_expanded expanded;
> +	} mode_select;
> +	u8	index;
> +	u8	array_name[ARRAY_LABEL_LEN];
> +	spinlock_t		ms_lock;
> +	int			ms_queued;
> +	struct work_struct	ms_work;
> +	struct scsi_device	*ms_sdev;
> +	struct list_head	ms_head;
> +};
> +
>  struct c2_inquiry {
>  	u8	peripheral_info;
>  	u8	page_code;	/* 0xC2 */
> @@ -369,16 +369,16 @@ static void release_controller(struct kref *kref)
>  	kfree(ctlr);
>  }
> 
> -static struct rdac_controller *get_controller(u8 *subsys_id, u8
> *slot_id,
> -						char *array_name)
> +static struct rdac_controller *get_controller(int index, char
> *array_name,
> +						u8 *array_id)
>  {
>  	struct rdac_controller *ctlr, *tmp;
> 
>  	spin_lock(&list_lock);
> 
>  	list_for_each_entry(tmp, &ctlr_list, node) {
> -		if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0)
> &&
> -			  (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
> +		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
> +			  (tmp->index == index)) {
>  			kref_get(&tmp->kref);
>  			spin_unlock(&list_lock);
>  			return tmp;
> @@ -389,16 +389,10 @@ static struct rdac_controller *get_controller(u8
> *subsys_id, u8 *slot_id,
>  		goto done;
> 
>  	/* initialize fields of controller */
> -	memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
> -	memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
> +	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
> +	ctlr->index = index;
>  	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
> 
> -	/* update the controller index */
> -	if (slot_id[1] == 0x31)
> -		ctlr->index = 0;
> -	else
> -		ctlr->index = 1;
> -
>  	kref_init(&ctlr->kref);
>  	ctlr->use_ms10 = -1;
>  	ctlr->ms_queued = 0;
> @@ -444,7 +438,7 @@ done:
>  }
> 
>  static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data
> *h,
> -			char *array_name)
> +			char *array_name, u8 *array_id)
>  {
>  	int err, i;
>  	struct c8_inquiry *inqp;
> @@ -463,6 +457,8 @@ static int get_lun_info(struct scsi_device *sdev,
> struct rdac_dh_data *h,
>  			*(array_name+i) = inqp->array_user_label[(2*i)+1];
> 
>  		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
> +		memset(array_id, 0, UNIQUE_ID_LEN);
> +		memcpy(array_id, inqp->array_unique_id, inqp-
> >array_uniq_id_len);
>  	}
>  	return err;
>  }
> @@ -504,16 +500,20 @@ static int check_ownership(struct scsi_device
> *sdev, struct rdac_dh_data *h)
>  }
> 
>  static int initialize_controller(struct scsi_device *sdev,
> -				 struct rdac_dh_data *h, char *array_name)
> +		struct rdac_dh_data *h, char *array_name, u8 *array_id)
>  {
> -	int err;
> +	int err, index;
>  	struct c4_inquiry *inqp;
> 
>  	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
>  	if (err == SCSI_DH_OK) {
>  		inqp = &h->inq.c4;
> -		h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id,
> -					array_name);
> +		/* get the controller index */
> +		if (inqp->slot_id[1] == 0x31)
> +			index = 0;
> +		else
> +			index = 1;
> +		h->ctlr = get_controller(index, array_name, array_id);
>  		if (!h->ctlr)
>  			err = SCSI_DH_RES_TEMP_UNAVAIL;
>  	}
> @@ -835,6 +835,7 @@ static int rdac_bus_attach(struct scsi_device *sdev)
>  	unsigned long flags;
>  	int err;
>  	char array_name[ARRAY_LABEL_LEN];
> +	char array_id[UNIQUE_ID_LEN];
> 
>  	scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
>  			       + sizeof(*h) , GFP_KERNEL);
> @@ -849,11 +850,11 @@ static int rdac_bus_attach(struct scsi_device
> *sdev)
>  	h->lun = UNINITIALIZED_LUN;
>  	h->state = RDAC_STATE_ACTIVE;
> 
> -	err = get_lun_info(sdev, h, array_name);
> +	err = get_lun_info(sdev, h, array_name, array_id);
>  	if (err != SCSI_DH_OK)
>  		goto failed;
> 
> -	err = initialize_controller(sdev, h, array_name);
> +	err = initialize_controller(sdev, h, array_name, array_id);
>  	if (err != SCSI_DH_OK)
>  		goto failed;
> 
> 
> 
> --
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