dasd_devmap.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 944 行 · 第 1/2 页

	spin_unlock(&dasd_devmap_lock);
	return device;
}

/*
 * Return devmap for cdev. If no devmap exists yet, create one and
 * connect it to the cdev.
 */
static struct dasd_devmap *
dasd_devmap_from_cdev(struct ccw_device *cdev)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(cdev->dev.bus_id);
	if (IS_ERR(devmap))
		devmap = dasd_add_busid(cdev->dev.bus_id,
					DASD_FEATURE_DEFAULT);
	return devmap;
}

/*
 * Create a dasd device structure for cdev.
 */
struct dasd_device *
dasd_create_device(struct ccw_device *cdev)
{
	struct dasd_devmap *devmap;
	struct dasd_device *device;
	int rc;

	devmap = dasd_devmap_from_cdev(cdev);
	if (IS_ERR(devmap))
		return (void *) devmap;
	cdev->dev.driver_data = devmap;

	device = dasd_alloc_device();
	if (IS_ERR(device))
		return device;
	atomic_set(&device->ref_count, 2);

	spin_lock(&dasd_devmap_lock);
	if (!devmap->device) {
		devmap->device = device;
		device->devindex = devmap->devindex;
		device->features = devmap->features;
		get_device(&cdev->dev);
		device->cdev = cdev;
		rc = 0;
	} else
		/* Someone else was faster. */
		rc = -EBUSY;
	spin_unlock(&dasd_devmap_lock);

	if (rc) {
		dasd_free_device(device);
		return ERR_PTR(rc);
	}
	return device;
}

/*
 * Wait queue for dasd_delete_device waits.
 */
static DECLARE_WAIT_QUEUE_HEAD(dasd_delete_wq);

/*
 * Remove a dasd device structure. The passed referenced
 * is destroyed.
 */
void
dasd_delete_device(struct dasd_device *device)
{
	struct ccw_device *cdev;
	struct dasd_devmap *devmap;

	/* First remove device pointer from devmap. */
	devmap = dasd_find_busid(device->cdev->dev.bus_id);
	BUG_ON(IS_ERR(devmap));
	spin_lock(&dasd_devmap_lock);
	if (devmap->device != device) {
		spin_unlock(&dasd_devmap_lock);
		dasd_put_device(device);
		return;
	}
	devmap->device = NULL;
	spin_unlock(&dasd_devmap_lock);

	/* Drop ref_count by 2, one for the devmap reference and
	 * one for the passed reference. */
	atomic_sub(2, &device->ref_count);

	/* Wait for reference counter to drop to zero. */
	wait_event(dasd_delete_wq, atomic_read(&device->ref_count) == 0);

	/* Disconnect dasd_device structure from ccw_device structure. */
	cdev = device->cdev;
	device->cdev = NULL;

	/* Disconnect dasd_devmap structure from ccw_device structure. */
	cdev->dev.driver_data = NULL;

	/* Put ccw_device structure. */
	put_device(&cdev->dev);

	/* Now the device structure can be freed. */
	dasd_free_device(device);
}

/*
 * Reference counter dropped to zero. Wake up waiter
 * in dasd_delete_device.
 */
void
dasd_put_device_wake(struct dasd_device *device)
{
	wake_up(&dasd_delete_wq);
}

/*
 * Return dasd_device structure associated with cdev.
 */
struct dasd_device *
dasd_device_from_cdev(struct ccw_device *cdev)
{
	struct dasd_devmap *devmap;
	struct dasd_device *device;

	device = ERR_PTR(-ENODEV);
	spin_lock(&dasd_devmap_lock);
	devmap = cdev->dev.driver_data;
	if (devmap && devmap->device) {
		device = devmap->device;
		dasd_get_device(device);
	}
	spin_unlock(&dasd_devmap_lock);
	return device;
}

/*
 * SECTION: files in sysfs
 */

/*
 * readonly controls the readonly status of a dasd
 */
static ssize_t
dasd_ro_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int ro_flag;

	devmap = dasd_find_busid(dev->bus_id);
	if (!IS_ERR(devmap))
		ro_flag = (devmap->features & DASD_FEATURE_READONLY) != 0;
	else
		ro_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_READONLY) != 0;
	return snprintf(buf, PAGE_SIZE, ro_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_ro_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	int ro_flag;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);
	ro_flag = buf[0] == '1';
	spin_lock(&dasd_devmap_lock);
	if (ro_flag)
		devmap->features |= DASD_FEATURE_READONLY;
	else
		devmap->features &= ~DASD_FEATURE_READONLY;
	if (devmap->device)
		devmap->device->features = devmap->features;
	if (devmap->device && devmap->device->gdp)
		set_disk_ro(devmap->device->gdp, ro_flag);
	spin_unlock(&dasd_devmap_lock);
	return count;
}

static DEVICE_ATTR(readonly, 0644, dasd_ro_show, dasd_ro_store);

/*
 * use_diag controls whether the driver should use diag rather than ssch
 * to talk to the device
 */
static ssize_t 
dasd_use_diag_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int use_diag;

	devmap = dasd_find_busid(dev->bus_id);
	if (!IS_ERR(devmap))
		use_diag = (devmap->features & DASD_FEATURE_USEDIAG) != 0;
	else
		use_diag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USEDIAG) != 0;
	return sprintf(buf, use_diag ? "1\n" : "0\n");
}

static ssize_t
dasd_use_diag_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	ssize_t rc;
	int use_diag;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);
	use_diag = buf[0] == '1';
	spin_lock(&dasd_devmap_lock);
	/* Changing diag discipline flag is only allowed in offline state. */
	rc = count;
	if (!devmap->device) {
		if (use_diag)
			devmap->features |= DASD_FEATURE_USEDIAG;
		else
			devmap->features &= ~DASD_FEATURE_USEDIAG;
	} else
		rc = -EPERM;
	spin_unlock(&dasd_devmap_lock);
	return rc;
}

static
DEVICE_ATTR(use_diag, 0644, dasd_use_diag_show, dasd_use_diag_store);

static ssize_t
dasd_discipline_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	char *dname;

	spin_lock(&dasd_devmap_lock);
	dname = "none";
	devmap = dev->driver_data;
	if (devmap && devmap->device && devmap->device->discipline)
		dname = devmap->device->discipline->name;
	spin_unlock(&dasd_devmap_lock);
	return snprintf(buf, PAGE_SIZE, "%s\n", dname);
}

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
 */
static ssize_t
dasd_eer_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int eer_flag;

	devmap = dasd_find_busid(dev->bus_id);
	if (!IS_ERR(devmap) && devmap->device)
		eer_flag = dasd_eer_enabled(devmap->device);
	else
		eer_flag = 0;
	return snprintf(buf, PAGE_SIZE, eer_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_eer_store(struct device *dev, struct device_attribute *attr,
	       const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	int rc;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);
	if (!devmap->device)
		return count;
	if (buf[0] == '1') {
		rc = dasd_eer_enable(devmap->device);
		if (rc)
			return rc;
	} else
		dasd_eer_disable(devmap->device);
	return count;
}

static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);

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,
};

static struct attribute_group dasd_attr_group = {
	.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;
}
EXPORT_SYMBOL(dasd_set_uid);

/*
 * Return value of the specified feature.
 */
int
dasd_get_feature(struct ccw_device *cdev, int feature)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(cdev->dev.bus_id);
	if (IS_ERR(devmap))
		return (int) PTR_ERR(devmap);

	return ((devmap->features & feature) != 0);
}

/*
 * Set / reset given feature.
 * Flag indicates wether to set (!=0) or the reset (=0) the feature.
 */
int
dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(cdev->dev.bus_id);
	if (IS_ERR(devmap))
		return (int) PTR_ERR(devmap);

	spin_lock(&dasd_devmap_lock);
	if (flag)
		devmap->features |= feature;
	else
		devmap->features &= ~feature;
	if (devmap->device)
		devmap->device->features = devmap->features;
	spin_unlock(&dasd_devmap_lock);
	return 0;
}


int
dasd_add_sysfs_files(struct ccw_device *cdev)
{
	return sysfs_create_group(&cdev->dev.kobj, &dasd_attr_group);
}

void
dasd_remove_sysfs_files(struct ccw_device *cdev)
{
	sysfs_remove_group(&cdev->dev.kobj, &dasd_attr_group);
}


int
dasd_devmap_init(void)
{
	int i;

	/* Initialize devmap structures. */
	dasd_max_devindex = 0;
	for (i = 0; i < 256; i++)
		INIT_LIST_HEAD(&dasd_hashlists[i]);
	return 0;

}

void
dasd_devmap_exit(void)
{
	dasd_forget_ranges();
}