staging: unisys: visorbus: remove unused sysfs attribute devmajorminor/*

The sysfs attribute directory at:

    /sys/bus/visorbus/devices/vbus<x>:dev<y>/devmajorminor/*

or

    /sys/devices/visorbus<x>/vbus<x>:dev<y>/devmajorminor/*

previously provided a location where a visorbus function driver could
publish information (for usermode use) about possibly-multiple major and
minor device numbers for character devices created for a each visorbus
device, using visorbus_registerdevnode().  This functionality is not
currently used, so it has been removed by this cset.

Signed-off-by: Tim Sell <Timothy.Sell@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/Documentation/overview.txt

@@ -137,12 +137,6 @@ called automatically by the visorbus driver at appropriate times:
 
 * The resume() function is the "book-end" to pause(), and is described above.
 
-If/when a function driver creates a Linux device (that needs to be accessed
-from usermode), it calls visorbus_registerdevnode(), passing the major and
-minor number of the device.  (Of course not all function drivers will need
-to do this.)  This simply creates the appropriate "devmajorminor" sysfs entry
-described below, so that a hotplug script can use it to create a device node.
-
 2.1.3. sysfs Advertised Information
 -----------------------------------
 
@@ -197,19 +191,6 @@ The following files exist under /sys/devices/visorbus<x>/vbus<x>:dev<y>:
                               if the appropriate function driver has not
                               been loaded yet.
 
-    devmajorminor
-
-        <devname>             if applicable, each file here identifies (via
-        ...                   its file contents) the
-                              "<major>:<minor>" needed for a device node to
-                              enable access from usermode.  There is exactly
-                              one file here for each different device node
-                              that can be accessed (from usermode).  Note
-                              that this info is provided by a particular
-                              function driver, so these will not exist
-                              until AFTER the appropriate function driver
-                              controlling this device class is loaded.
-
     channel                   properties of the device channel (all in
                               ascii text format)
 

drivers/staging/unisys/include/visorbus.h

@@ -136,7 +136,6 @@ struct visor_device {
 	struct periodic_work *periodic_work;
 	bool being_removed;
 	bool responded_to_device_create;
-	struct kobject kobjdevmajorminor; /* visorbus<x>/dev<y>/devmajorminor/*/
 	struct {
 		int major, minor;
 		void *attr;	/* private use by devmajorminor_attr.c you can
@@ -174,8 +173,6 @@ int visorbus_write_channel(struct visor_device *dev,
 			   unsigned long nbytes);
 int visorbus_clear_channel(struct visor_device *dev,
 			   unsigned long offset, u8 ch, unsigned long nbytes);
-int visorbus_registerdevnode(struct visor_device *dev,
-			     const char *name, int major, int minor);
 void visorbus_enable_channel_interrupts(struct visor_device *dev);
 void visorbus_disable_channel_interrupts(struct visor_device *dev);
 #endif

drivers/staging/unisys/visorbus/visorbus_main.c

@@ -243,180 +243,6 @@ visorbus_release_device(struct device *xdev)
 	kfree(dev);
 }
 
-/* Implement publishing of device node attributes under:
- *
- *     /sys/bus/visorbus<x>/dev<y>/devmajorminor
- *
- */
-
-#define to_devmajorminor_attr(_attr) \
-	container_of(_attr, struct devmajorminor_attribute, attr)
-#define to_visor_device_from_kobjdevmajorminor(obj) \
-	container_of(obj, struct visor_device, kobjdevmajorminor)
-
-struct devmajorminor_attribute {
-	struct attribute attr;
-	int slot;
-	ssize_t (*show)(struct visor_device *, int slot, char *buf);
-	ssize_t (*store)(struct visor_device *, int slot, const char *buf,
-			 size_t count);
-};
-
-static ssize_t DEVMAJORMINOR_ATTR(struct visor_device *dev, int slot, char *buf)
-{
-	int maxdevnodes = ARRAY_SIZE(dev->devnodes) / sizeof(dev->devnodes[0]);
-
-	if (slot < 0 || slot >= maxdevnodes)
-		return 0;
-	return snprintf(buf, PAGE_SIZE, "%d:%d\n",
-			dev->devnodes[slot].major, dev->devnodes[slot].minor);
-}
-
-static ssize_t
-devmajorminor_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
-{
-	struct devmajorminor_attribute *devmajorminor_attr =
-	    to_devmajorminor_attr(attr);
-	struct visor_device *dev = to_visor_device_from_kobjdevmajorminor(kobj);
-	ssize_t ret = 0;
-
-	if (devmajorminor_attr->show)
-		ret = devmajorminor_attr->show(dev,
-					       devmajorminor_attr->slot, buf);
-	return ret;
-}
-
-static ssize_t
-devmajorminor_attr_store(struct kobject *kobj,
-			 struct attribute *attr, const char *buf, size_t count)
-{
-	struct devmajorminor_attribute *devmajorminor_attr =
-	    to_devmajorminor_attr(attr);
-	struct visor_device *dev = to_visor_device_from_kobjdevmajorminor(kobj);
-	ssize_t ret = 0;
-
-	if (devmajorminor_attr->store)
-		ret = devmajorminor_attr->store(dev,
-						devmajorminor_attr->slot,
-						buf, count);
-	return ret;
-}
-
-static int register_devmajorminor_attributes(struct visor_device *dev);
-
-static int
-devmajorminor_create_file(struct visor_device *dev, const char *name,
-			  int major, int minor)
-{
-	int maxdevnodes = ARRAY_SIZE(dev->devnodes) / sizeof(dev->devnodes[0]);
-	struct devmajorminor_attribute *myattr = NULL;
-	int x = -1, rc = 0, slot = -1;
-
-	register_devmajorminor_attributes(dev);
-	for (slot = 0; slot < maxdevnodes; slot++)
-		if (!dev->devnodes[slot].attr)
-			break;
-	if (slot == maxdevnodes) {
-		rc = -ENOMEM;
-		goto away;
-	}
-	myattr = kzalloc(sizeof(*myattr), GFP_KERNEL);
-	if (!myattr) {
-		rc = -ENOMEM;
-		goto away;
-	}
-	myattr->show = DEVMAJORMINOR_ATTR;
-	myattr->store = NULL;
-	myattr->slot = slot;
-	myattr->attr.name = name;
-	myattr->attr.mode = S_IRUGO;
-	dev->devnodes[slot].attr = myattr;
-	dev->devnodes[slot].major = major;
-	dev->devnodes[slot].minor = minor;
-	x = sysfs_create_file(&dev->kobjdevmajorminor, &myattr->attr);
-	if (x < 0) {
-		rc = x;
-		goto away;
-	}
-	kobject_uevent(&dev->device.kobj, KOBJ_ONLINE);
-away:
-	if (rc < 0) {
-		kfree(myattr);
-		myattr = NULL;
-		dev->devnodes[slot].attr = NULL;
-	}
-	return rc;
-}
-
-static void
-devmajorminor_remove_file(struct visor_device *dev, int slot)
-{
-	int maxdevnodes = ARRAY_SIZE(dev->devnodes) / sizeof(dev->devnodes[0]);
-	struct devmajorminor_attribute *myattr = NULL;
-
-	if (slot < 0 || slot >= maxdevnodes)
-		return;
-	myattr = (struct devmajorminor_attribute *)(dev->devnodes[slot].attr);
-	if (!myattr)
-		return;
-	sysfs_remove_file(&dev->kobjdevmajorminor, &myattr->attr);
-	kobject_uevent(&dev->device.kobj, KOBJ_OFFLINE);
-	dev->devnodes[slot].attr = NULL;
-	kfree(myattr);
-}
-
-static void
-devmajorminor_remove_all_files(struct visor_device *dev)
-{
-	int i = 0;
-	int maxdevnodes = ARRAY_SIZE(dev->devnodes) / sizeof(dev->devnodes[0]);
-
-	for (i = 0; i < maxdevnodes; i++)
-		devmajorminor_remove_file(dev, i);
-}
-
-static const struct sysfs_ops devmajorminor_sysfs_ops = {
-	.show = devmajorminor_attr_show,
-	.store = devmajorminor_attr_store,
-};
-
-static struct kobj_type devmajorminor_kobj_type = {
-	.sysfs_ops = &devmajorminor_sysfs_ops
-};
-
-static int
-register_devmajorminor_attributes(struct visor_device *dev)
-{
-	int rc = 0, x = 0;
-
-	if (dev->kobjdevmajorminor.parent)
-		goto away;	/* already registered */
-	x = kobject_init_and_add(&dev->kobjdevmajorminor,
-				 &devmajorminor_kobj_type, &dev->device.kobj,
-				 "devmajorminor");
-	if (x < 0) {
-		rc = x;
-		goto away;
-	}
-
-	kobject_uevent(&dev->kobjdevmajorminor, KOBJ_ADD);
-
-away:
-	return rc;
-}
-
-static void
-unregister_devmajorminor_attributes(struct visor_device *dev)
-{
-	if (!dev->kobjdevmajorminor.parent)
-		return;		/* already unregistered */
-	devmajorminor_remove_all_files(dev);
-
-	kobject_del(&dev->kobjdevmajorminor);
-	kobject_put(&dev->kobjdevmajorminor);
-	dev->kobjdevmajorminor.parent = NULL;
-}
-
 /* begin implementation of specific channel attributes to appear under
 * /sys/bus/visorbus<x>/dev<y>/channel
 */
@@ -801,7 +627,6 @@ visordriver_remove_device(struct device *xdev)
 	}
 	up(&dev->visordriver_callback_lock);
 	dev_stop_periodic_work(dev);
-	devmajorminor_remove_all_files(dev);
 
 	put_device(&dev->device);
 
@@ -920,14 +745,6 @@ visorbus_clear_channel(struct visor_device *dev, unsigned long offset, u8 ch,
 }
 EXPORT_SYMBOL_GPL(visorbus_clear_channel);
 
-int
-visorbus_registerdevnode(struct visor_device *dev,
-			 const char *name, int major, int minor)
-{
-	return devmajorminor_create_file(dev, name, major, minor);
-}
-EXPORT_SYMBOL_GPL(visorbus_registerdevnode);
-
 /** We don't really have a real interrupt, so for now we just call the
  *  interrupt function periodically...
  */
@@ -1018,19 +835,9 @@ create_visor_device(struct visor_device *dev)
 		goto away;
 	}
 
-	rc = register_devmajorminor_attributes(dev);
-	if (rc < 0) {
-		POSTCODE_LINUX_3(DEVICE_REGISTER_FAILURE_PC, chipset_dev_no,
-				 DIAG_SEVERITY_ERR);
-		goto away_unregister;
-	}
-
 	list_add_tail(&dev->list_all, &list_all_device_instances);
 	return 0;
 
-away_unregister:
-	device_unregister(&dev->device);
-
 away:
 	put_device(&dev->device);
 	return rc;
@@ -1040,7 +847,6 @@ static void
 remove_visor_device(struct visor_device *dev)
 {
 	list_del(&dev->list_all);
-	unregister_devmajorminor_attributes(dev);
 	put_device(&dev->device);
 	device_unregister(&dev->device);
 }