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>

1 files changed, 105 insertions, 40 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 91a0367d583e..3599ab2506d2 100644
--- 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;
 }