[patch 13/13] s390: dasd device identifiers.

[patch 13/13] s390: dasd device identifiers.

[Martin Schwidefsky]

From: Horst Hummel <horst.hummel@de.ibm.com>

[patch 13/13] s390: dasd device identifiers.

Generate new sysfs-attribute 'uid' that contains an device specific
unique identifier. This can be used to identity multiple ALIASES of
the same physical device (PAV). In addition the sysfs-attributes
'vendor' (containing the manufacturer of the device) and 'alias'
(identify alias or base device) is added.
This is first part of PAV support in LPAR (also valid on zVM).

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

 drivers/s390/block/dasd_devmap.c |  101 +++++++++++++++++++++++++++++++++++++++
 drivers/s390/block/dasd_eckd.c   |   51 ++++++++++++++++++-
 drivers/s390/block/dasd_eckd.h   |   46 ++++++++++-------
 drivers/s390/block/dasd_int.h    |   12 ++++
 4 files changed, 190 insertions(+), 20 deletions(-)

diff -urpN linux-2.6/drivers/s390/block/dasd_devmap.c linux-2.6-patched/drivers/s390/block/dasd_devmap.c
--- linux-2.6/drivers/s390/block/dasd_devmap.c	2006-04-24 16:47:00.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd_devmap.c	2006-04-24 16:47:31.000000000 +0200
@@ -45,6 +45,7 @@ struct dasd_devmap {
         unsigned int devindex;
         unsigned short features;
 	struct dasd_device *device;
+	struct dasd_uid uid;
 };
 
 /*
@@ -716,6 +717,68 @@ dasd_discipline_show(struct device *dev,
 
 static DEVICE_ATTR(discipline, 0444, dasd_discipline_show, NULL);
 
+static ssize_t
+dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	int alias;
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap))
+		alias = devmap->uid.alias;
+	else
+		alias = 0;
+	spin_unlock(&dasd_devmap_lock);
+
+	return sprintf(buf, alias ? "1\n" : "0\n");
+}
+
+static DEVICE_ATTR(alias, 0444, dasd_alias_show, NULL);
+
+static ssize_t
+dasd_vendor_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	char *vendor;
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
+		vendor = devmap->uid.vendor;
+	else
+		vendor = "";
+	spin_unlock(&dasd_devmap_lock);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
+}
+
+static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);
+
+#define UID_STRLEN ( /* vendor */ 3 + 1 + /* serial    */ 14 + 1 +\
+		     /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1)
+
+static ssize_t
+dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	char uid[UID_STRLEN];
+
+	devmap = dasd_find_busid(dev->bus_id);
+	spin_lock(&dasd_devmap_lock);
+	if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
+		snprintf(uid, sizeof(uid), "%s.%s.%04x.%02x",
+			 devmap->uid.vendor, devmap->uid.serial,
+			 devmap->uid.ssid, devmap->uid.unit_addr);
+	else
+		uid[0] = 0;
+	spin_unlock(&dasd_devmap_lock);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", uid);
+}
+
+static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);
+
 /*
  * extended error-reporting
  */
@@ -759,6 +822,9 @@ static DEVICE_ATTR(eer_enabled, 0644, da
 static struct attribute * dasd_attrs[] = {
 	&dev_attr_readonly.attr,
 	&dev_attr_discipline.attr,
+	&dev_attr_alias.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_uid.attr,
 	&dev_attr_use_diag.attr,
 	&dev_attr_eer_enabled.attr,
 	NULL,
@@ -768,6 +834,41 @@ static struct attribute_group dasd_attr_
 	.attrs = dasd_attrs,
 };
 
+
+/*
+ * Return copy of the device unique identifier.
+ */
+int
+dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
+{
+	struct dasd_devmap *devmap;
+
+	devmap = dasd_find_busid(cdev->dev.bus_id);
+	if (IS_ERR(devmap))
+		return PTR_ERR(devmap);
+	spin_lock(&dasd_devmap_lock);
+	*uid = devmap->uid;
+	spin_unlock(&dasd_devmap_lock);
+	return 0;
+}
+
+/*
+ * Register the given device unique identifier into devmap struct.
+ */
+int
+dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
+{
+	struct dasd_devmap *devmap;
+
+	devmap = dasd_find_busid(cdev->dev.bus_id);
+	if (IS_ERR(devmap))
+		return PTR_ERR(devmap);
+	spin_lock(&dasd_devmap_lock);
+	devmap->uid = *uid;
+	spin_unlock(&dasd_devmap_lock);
+	return 0;
+}
+
 /*
  * Return value of the specified feature.
  */
diff -urpN linux-2.6/drivers/s390/block/dasd_eckd.c linux-2.6-patched/drivers/s390/block/dasd_eckd.c
--- linux-2.6/drivers/s390/block/dasd_eckd.c	2006-04-24 16:47:00.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd_eckd.c	2006-04-24 16:47:31.000000000 +0200
@@ -446,6 +446,39 @@ dasd_eckd_cdl_reclen(int recid)
 	return LABEL_SIZE;
 }
 
+/*
+ * Generate device unique id that specifies the physical device.
+ */
+static int
+dasd_eckd_generate_uid(struct dasd_device *device, struct dasd_uid *uid)
+{
+	struct dasd_eckd_private *private;
+	struct dasd_eckd_confdata *confdata;
+
+	private = (struct dasd_eckd_private *) device->private;
+	if (!private)
+		return -ENODEV;
+	confdata = &private->conf_data;
+	if (!confdata)
+		return -ENODEV;
+
+	memset(uid, 0, sizeof(struct dasd_uid));
+	strncpy(uid->vendor, confdata->ned1.HDA_manufacturer,
+		sizeof(uid->vendor) - 1);
+	EBCASC(uid->vendor, sizeof(uid->vendor) - 1);
+	strncpy(uid->serial, confdata->ned1.HDA_location,
+		sizeof(uid->serial) - 1);
+	EBCASC(uid->serial, sizeof(uid->serial) - 1);
+	uid->ssid = confdata->neq.subsystemID;
+	if (confdata->ned2.sneq.flags == 0x40) {
+		uid->alias = 1;
+		uid->unit_addr = confdata->ned2.sneq.base_unit_addr;
+	} else
+		uid->unit_addr = confdata->ned1.unit_addr;
+
+	return 0;
+}
+
 static int
 dasd_eckd_read_conf(struct dasd_device *device)
 {
@@ -507,11 +540,15 @@ dasd_eckd_read_conf(struct dasd_device *
 	return 0;
 }
 
-
+/*
+ * Check device characteristics.
+ * If the device is accessible using ECKD discipline, the device is enabled.
+ */
 static int
 dasd_eckd_check_characteristics(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private;
+	struct dasd_uid uid;
 	void *rdc_data;
 	int rc;
 
@@ -536,6 +573,7 @@ dasd_eckd_check_characteristics(struct d
 
 	/* Read Device Characteristics */
 	rdc_data = (void *) &(private->rdc_data);
+	memset(rdc_data, 0, sizeof(rdc_data));
 	rc = read_dev_chars(device->cdev, &rdc_data, 64);
 	if (rc) {
 		DEV_MESSAGE(KERN_WARNING, device,
@@ -556,8 +594,17 @@ dasd_eckd_check_characteristics(struct d
 
 	/* Read Configuration Data */
 	rc = dasd_eckd_read_conf (device);
-	return rc;
+	if (rc)
+		return rc;
+
+	/* Generate device unique id and register in devmap */
+	rc = dasd_eckd_generate_uid(device, &uid);
+	if (rc)
+		return rc;
 
+	rc = dasd_set_uid(device->cdev, &uid);
+
+	return rc;
 }
 
 static struct dasd_ccw_req *
diff -urpN linux-2.6/drivers/s390/block/dasd_eckd.h linux-2.6-patched/drivers/s390/block/dasd_eckd.h
--- linux-2.6/drivers/s390/block/dasd_eckd.h	2006-04-24 16:47:00.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd_eckd.h	2006-04-24 16:47:31.000000000 +0200
@@ -228,26 +228,36 @@ struct dasd_eckd_confdata {
 		unsigned char HDA_manufacturer[3];
 		unsigned char HDA_location[2];
 		unsigned char HDA_seqno[12];
-		__u16 ID;
+		__u8 ID;
+		__u8 unit_addr;
 	} __attribute__ ((packed)) ned1;
-	struct {
+	union {
 		struct {
-			unsigned char identifier:2;
-			unsigned char token_id:1;
-			unsigned char sno_valid:1;
-			unsigned char subst_sno:1;
-			unsigned char recNED:1;
-			unsigned char emuNED:1;
-			unsigned char reserved:1;
-		} __attribute__ ((packed)) flags;
-		__u8 descriptor;
-		__u8 reserved[2];
-		unsigned char dev_type[6];
-		unsigned char dev_model[3];
-		unsigned char DASD_manufacturer[3];
-		unsigned char DASD_location[2];
-		unsigned char DASD_seqno[12];
-		__u16 ID;
+			struct {
+				unsigned char identifier:2;
+				unsigned char token_id:1;
+				unsigned char sno_valid:1;
+				unsigned char subst_sno:1;
+				unsigned char recNED:1;
+				unsigned char emuNED:1;
+				unsigned char reserved:1;
+			} __attribute__ ((packed)) flags;
+			__u8 descriptor;
+			__u8 reserved[2];
+			unsigned char dev_type[6];
+			unsigned char dev_model[3];
+			unsigned char DASD_manufacturer[3];
+			unsigned char DASD_location[2];
+			unsigned char DASD_seqno[12];
+			__u16 ID;
+		} __attribute__ ((packed)) ned;
+		struct {
+			unsigned char flags;            /* byte  0    */
+			unsigned char res2[7];          /* byte  1- 7 */
+			unsigned char sua_flags;	/* byte  8    */
+			__u8 base_unit_addr;            /* byte  9    */
+			unsigned char res3[22];	        /* byte 10-31 */
+		} __attribute__ ((packed)) sneq;
 	} __attribute__ ((packed)) ned2;
 	struct {
 		struct {
diff -urpN linux-2.6/drivers/s390/block/dasd_int.h linux-2.6-patched/drivers/s390/block/dasd_int.h
--- linux-2.6/drivers/s390/block/dasd_int.h	2006-04-24 16:47:00.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd_int.h	2006-04-24 16:47:31.000000000 +0200
@@ -268,6 +268,16 @@ struct dasd_discipline {
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
 
+/*
+ * Unique identifier for dasd device.
+ */
+struct dasd_uid {
+	__u8 alias;
+	char vendor[4];
+	char serial[15];
+	__u16 ssid;
+	__u8 unit_addr;
+};
 
 /*
  * Notification numbers for extended error reporting notifications:
@@ -516,6 +526,8 @@ void dasd_devmap_exit(void);
 struct dasd_device *dasd_create_device(struct ccw_device *);
 void dasd_delete_device(struct dasd_device *);
 
+int dasd_get_uid(struct ccw_device *, struct dasd_uid *);
+int dasd_set_uid(struct ccw_device *, struct dasd_uid *);
 int dasd_get_feature(struct ccw_device *, int);
 int dasd_set_feature(struct ccw_device *, int, int);
 

Re: [patch 13/13] s390: dasd device identifiers.

[Andrew Morton]

Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:
>
> @@ -45,6 +45,7 @@ struct dasd_devmap {
>          unsigned int devindex;
>          unsigned short features;
>  	struct dasd_device *device;
> +	struct dasd_uid uid;
>  };

Someone's missing a TAB key.

> +static ssize_t
> +dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct dasd_devmap *devmap;
> +	int alias;
> +
> +	devmap = dasd_find_busid(dev->bus_id);
> +	spin_lock(&dasd_devmap_lock);
> +	if (!IS_ERR(devmap))
> +		alias = devmap->uid.alias;
> +	else
> +		alias = 0;
> +	spin_unlock(&dasd_devmap_lock);
> +
> +	return sprintf(buf, alias ? "1\n" : "0\n");
> +}

The locking is suspicious.  We take a spinlock just for a single read?

> +/*
> + * Return copy of the device unique identifier.
> + */
> +int
> +dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
> +{
> +	struct dasd_devmap *devmap;
> +
> +	devmap = dasd_find_busid(cdev->dev.bus_id);
> +	if (IS_ERR(devmap))
> +		return PTR_ERR(devmap);
> +	spin_lock(&dasd_devmap_lock);
> +	*uid = devmap->uid;
> +	spin_unlock(&dasd_devmap_lock);
> +	return 0;
> +}

And for a single write?

Re: [patch 13/13] s390: dasd device identifiers.

[Martin Schwidefsky]

On Mon, 2006-04-24 at 16:49 -0700, Andrew Morton wrote:
> Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:
> >
> > @@ -45,6 +45,7 @@ struct dasd_devmap {
> >          unsigned int devindex;
> >          unsigned short features;
> >  	struct dasd_device *device;
> > +	struct dasd_uid uid;
> >  };
> 
> Someone's missing a TAB key.

I have to find some script that checks for the damned tabs.

> > +static ssize_t
> > +dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
> > +{
> > +	struct dasd_devmap *devmap;
> > +	int alias;
> > +
> > +	devmap = dasd_find_busid(dev->bus_id);
> > +	spin_lock(&dasd_devmap_lock);
> > +	if (!IS_ERR(devmap))
> > +		alias = devmap->uid.alias;
> > +	else
> > +		alias = 0;
> > +	spin_unlock(&dasd_devmap_lock);
> > +
> > +	return sprintf(buf, alias ? "1\n" : "0\n");
> > +}
> 
> The locking is suspicious.  We take a spinlock just for a single read?

We could remove the locking for single read/writes, devmap structures
are never deleted so it is safe to access a single value after the
dasd_find_busid. But it is not so easy for the vendor and serial string,
these are not single values so we need some kind of locking. To keep
things symmetrical the lock is used for alias as well. There is a bug
though, only the pointer to the vendor/serial string is read under the
lock, the copy is done outside the lock. If that races with a
dasd_set_uid call funny things might happen. The copy needs to be done
inside the lock. Horst ?

-- 
blue skies,
  Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.

Re: [patch 13/13] s390: dasd device identifiers.

[Jan Blunck]

On 4/24/06, Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:
> +/*
> + * Register the given device unique identifier into devmap struct.
> + */
> +int
> +dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
> +{
> +       struct dasd_devmap *devmap;
> +
> +       devmap = dasd_find_busid(cdev->dev.bus_id);
> +       if (IS_ERR(devmap))
> +               return PTR_ERR(devmap);
> +       spin_lock(&dasd_devmap_lock);
> +       devmap->uid = *uid;
> +       spin_unlock(&dasd_devmap_lock);
> +       return 0;
> +}
> +

EXPORT_SYMBOL(dasd_set_uid) is missing.