Driver core: check return code of sysfs_create_link()

Check for return value of sysfs_create_link() in device_add() and
device_rename().  Add helper functions device_add_class_symlinks() and
device_remove_class_symlinks() to make the code easier to read.

[akpm@linux-foundation.org: fix unused var warnings]

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 91a0367..3599ab2 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -660,6 +660,82 @@ static int setup_parent(struct device *dev, struct device *parent)
        return 0;
 }
 
+static int device_add_class_symlinks(struct device *dev)
+{
+       int error;
+
+       if (!dev->class)
+               return 0;
+       error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
+                                 "subsystem");
+       if (error)
+               goto out;
+       /*
+        * If this is not a "fake" compatible device, then create the
+        * symlink from the class to the device.
+        */
+       if (dev->kobj.parent != &dev->class->subsys.kobj) {
+               error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
+                                         dev->bus_id);
+               if (error)
+                       goto out_subsys;
+       }
+       /* only bus-device parents get a "device"-link */
+       if (dev->parent && dev->parent->bus) {
+               error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
+                                         "device");
+               if (error)
+                       goto out_busid;
+#ifdef CONFIG_SYSFS_DEPRECATED
+               {
+                       char * class_name = make_class_name(dev->class->name,
+                                                               &dev->kobj);
+                       if (class_name)
+                               error = sysfs_create_link(&dev->parent->kobj,
+                                                       &dev->kobj, class_name);
+                       kfree(class_name);
+                       if (error)
+                               goto out_device;
+               }
+#endif
+       }
+       return 0;
+
+#ifdef CONFIG_SYSFS_DEPRECATED
+out_device:
+       if (dev->parent)
+               sysfs_remove_link(&dev->kobj, "device");
+#endif
+out_busid:
+       if (dev->kobj.parent != &dev->class->subsys.kobj)
+               sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+out_subsys:
+       sysfs_remove_link(&dev->kobj, "subsystem");
+out:
+       return error;
+}
+
+static void device_remove_class_symlinks(struct device *dev)
+{
+       if (!dev->class)
+               return;
+       if (dev->parent) {
+#ifdef CONFIG_SYSFS_DEPRECATED
+               char *class_name;
+
+               class_name = make_class_name(dev->class->name, &dev->kobj);
+               if (class_name) {
+                       sysfs_remove_link(&dev->parent->kobj, class_name);
+                       kfree(class_name);
+               }
+#endif
+               sysfs_remove_link(&dev->kobj, "device");
+       }
+       if (dev->kobj.parent != &dev->class->subsys.kobj)
+               sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+       sysfs_remove_link(&dev->kobj, "subsystem");
+}
+
 /**
  *     device_add - add device to device hierarchy.
  *     @dev:   device.
@@ -674,7 +750,6 @@ static int setup_parent(struct device *dev, struct device *parent)
 int device_add(struct device *dev)
 {
        struct device *parent = NULL;
-       char *class_name = NULL;
        struct class_interface *class_intf;
        int error = -EINVAL;
 
@@ -714,27 +789,9 @@ int device_add(struct device *dev)
                        goto ueventattrError;
        }
 
-       if (dev->class) {
-               sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
-                                 "subsystem");
-               /* If this is not a "fake" compatible device, then create the
-                * symlink from the class to the device. */
-               if (dev->kobj.parent != &dev->class->subsys.kobj)
-                       sysfs_create_link(&dev->class->subsys.kobj,
-                                         &dev->kobj, dev->bus_id);
-               if (parent) {
-                       sysfs_create_link(&dev->kobj, &dev->parent->kobj,
-                                                       "device");
-#ifdef CONFIG_SYSFS_DEPRECATED
-                       class_name = make_class_name(dev->class->name,
-                                                       &dev->kobj);
-                       if (class_name)
-                               sysfs_create_link(&dev->parent->kobj,
-                                                 &dev->kobj, class_name);
-#endif
-               }
-       }
-
+       error = device_add_class_symlinks(dev);
+       if (error)
+               goto SymlinkError;
        error = device_add_attrs(dev);
        if (error)
                goto AttrsError;
@@ -761,7 +818,6 @@ int device_add(struct device *dev)
                up(&dev->class->sem);
        }
  Done:
-       kfree(class_name);
        put_device(dev);
        return error;
  BusError:
@@ -772,6 +828,8 @@ int device_add(struct device *dev)
                                             BUS_NOTIFY_DEL_DEVICE, dev);
        device_remove_attrs(dev);
  AttrsError:
+       device_remove_class_symlinks(dev);
+ SymlinkError:
        if (MAJOR(dev->devt))
                device_remove_file(dev, &devt_attr);
 
@@ -1156,7 +1214,7 @@ int device_rename(struct device *dev, char *new_name)
 {
        char *old_class_name = NULL;
        char *new_class_name = NULL;
-       char *old_symlink_name = NULL;
+       char *old_device_name = NULL;
        int error;
 
        dev = get_device(dev);
@@ -1170,42 +1228,49 @@ int device_rename(struct device *dev, char *new_name)
                old_class_name = make_class_name(dev->class->name, &dev->kobj);
 #endif
 
-       if (dev->class) {
-               old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
-               if (!old_symlink_name) {
-                       error = -ENOMEM;
-                       goto out_free_old_class;
-               }
-               strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE);
+       old_device_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
+       if (!old_device_name) {
+               error = -ENOMEM;
+               goto out;
        }
-
+       strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
        strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
 
        error = kobject_rename(&dev->kobj, new_name);
+       if (error) {
+               strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
+               goto out;
+       }
 
 #ifdef CONFIG_SYSFS_DEPRECATED
        if (old_class_name) {
                new_class_name = make_class_name(dev->class->name, &dev->kobj);
                if (new_class_name) {
-                       sysfs_create_link(&dev->parent->kobj, &dev->kobj,
-                                         new_class_name);
+                       error = sysfs_create_link(&dev->parent->kobj,
+                                                 &dev->kobj, new_class_name);
+                       if (error)
+                               goto out;
                        sysfs_remove_link(&dev->parent->kobj, old_class_name);
                }
        }
 #endif
 
        if (dev->class) {
-               sysfs_remove_link(&dev->class->subsys.kobj,
-                                 old_symlink_name);
-               sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
-                                 dev->bus_id);
+               sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
+               error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
+                                         dev->bus_id);
+               if (error) {
+                       /* Uh... how to unravel this if restoring can fail? */
+                       dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
+                               __FUNCTION__, error);
+               }
        }
+out:
        put_device(dev);
 
        kfree(new_class_name);
-       kfree(old_symlink_name);
- out_free_old_class:
        kfree(old_class_name);
+       kfree(old_device_name);
 
        return error;
 }