s390/dasd: Make use of dasd_set_feature() more often

When setting certain attributes, we actually set the according feature
flag. Do this by using dasd_set_feature() at a few occurrences and
remove duplicate code.

In dasd_set_feature() dasd_find_busid() is used to retrieve the devmap
for the device in question. Combined with the change above, this would
require the device to be set online at least once so that a devmap is
being created. Change that by using dasd_devmap_from_cdev() instead,
which uses dasd_find_busid() first and will create a devmap accordingly
if there is none yet.
Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd_devmap.c

@@ -725,25 +725,15 @@ static ssize_t dasd_ff_show(struct device *dev, struct device_attribute *attr,
 static ssize_t dasd_ff_store(struct device *dev, struct device_attribute *attr,
 	      const char *buf, size_t count)
 {
-	struct dasd_devmap *devmap;
 	unsigned int val;
-
-	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
-	if (IS_ERR(devmap))
-		return PTR_ERR(devmap);
+	int rc;
 
 	if (kstrtouint(buf, 0, &val) || val > 1)
 		return -EINVAL;
 
-	spin_lock(&dasd_devmap_lock);
-	if (val)
-		devmap->features |= DASD_FEATURE_FAILFAST;
-	else
-		devmap->features &= ~DASD_FEATURE_FAILFAST;
-	if (devmap->device)
-		devmap->device->features = devmap->features;
-	spin_unlock(&dasd_devmap_lock);
-	return count;
+	rc = dasd_set_feature(to_ccwdev(dev), DASD_FEATURE_FAILFAST, val);
+
+	return rc ? : count;
 }
 
 static DEVICE_ATTR(failfast, 0644, dasd_ff_show, dasd_ff_store);
@@ -769,30 +759,28 @@ static ssize_t
 dasd_ro_store(struct device *dev, struct device_attribute *attr,
 	      const char *buf, size_t count)
 {
-	struct dasd_devmap *devmap;
+	struct ccw_device *cdev = to_ccwdev(dev);
 	struct dasd_device *device;
 	unsigned int val;
-
-	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
-	if (IS_ERR(devmap))
-		return PTR_ERR(devmap);
+	int rc;
 
 	if (kstrtouint(buf, 0, &val) || val > 1)
 		return -EINVAL;
 
-	spin_lock(&dasd_devmap_lock);
-	if (val)
-		devmap->features |= DASD_FEATURE_READONLY;
-	else
-		devmap->features &= ~DASD_FEATURE_READONLY;
-	device = devmap->device;
-	if (device) {
-		device->features = devmap->features;
-		val = val || test_bit(DASD_FLAG_DEVICE_RO, &device->flags);
-	}
-	spin_unlock(&dasd_devmap_lock);
-	if (device && device->block && device->block->gdp)
+	rc = dasd_set_feature(cdev, DASD_FEATURE_READONLY, val);
+	if (rc)
+		return rc;
+
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	val = val || test_bit(DASD_FLAG_DEVICE_RO, &device->flags);
+	if (device->block && device->block->gdp)
 		set_disk_ro(device->block->gdp, val);
+
+	dasd_put_device(device);
+
 	return count;
 }
 
@@ -819,25 +807,15 @@ static ssize_t
 dasd_erplog_store(struct device *dev, struct device_attribute *attr,
 	      const char *buf, size_t count)
 {
-	struct dasd_devmap *devmap;
 	unsigned int val;
-
-	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
-	if (IS_ERR(devmap))
-		return PTR_ERR(devmap);
+	int rc;
 
 	if (kstrtouint(buf, 0, &val) || val > 1)
 		return -EINVAL;
 
-	spin_lock(&dasd_devmap_lock);
-	if (val)
-		devmap->features |= DASD_FEATURE_ERPLOG;
-	else
-		devmap->features &= ~DASD_FEATURE_ERPLOG;
-	if (devmap->device)
-		devmap->device->features = devmap->features;
-	spin_unlock(&dasd_devmap_lock);
-	return count;
+	rc = dasd_set_feature(to_ccwdev(dev), DASD_FEATURE_ERPLOG, val);
+
+	return rc ? : count;
 }
 
 static DEVICE_ATTR(erplog, 0644, dasd_erplog_show, dasd_erplog_store);
@@ -1376,27 +1354,17 @@ static ssize_t dasd_reservation_policy_store(struct device *dev,
 					     struct device_attribute *attr,
 					     const char *buf, size_t count)
 {
-	struct dasd_devmap *devmap;
+	struct ccw_device *cdev = to_ccwdev(dev);
 	int rc;
 
-	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
-	if (IS_ERR(devmap))
-		return PTR_ERR(devmap);
-	rc = 0;
-	spin_lock(&dasd_devmap_lock);
 	if (sysfs_streq("ignore", buf))
-		devmap->features &= ~DASD_FEATURE_FAILONSLCK;
+		rc = dasd_set_feature(cdev, DASD_FEATURE_FAILONSLCK, 0);
 	else if (sysfs_streq("fail", buf))
-		devmap->features |= DASD_FEATURE_FAILONSLCK;
+		rc = dasd_set_feature(cdev, DASD_FEATURE_FAILONSLCK, 1);
 	else
 		rc = -EINVAL;
-	if (devmap->device)
-		devmap->device->features = devmap->features;
-	spin_unlock(&dasd_devmap_lock);
-	if (rc)
-		return rc;
-	else
-		return count;
+
+	return rc ? : count;
 }
 
 static DEVICE_ATTR(reservation_policy, 0644,
@@ -1522,7 +1490,7 @@ dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
 {
 	struct dasd_devmap *devmap;
 
-	devmap = dasd_find_busid(dev_name(&cdev->dev));
+	devmap = dasd_devmap_from_cdev(cdev);
 	if (IS_ERR(devmap))
 		return PTR_ERR(devmap);