1 files changed, 25 insertions, 59 deletions

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 27d1785b764..a271c87c447 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -20,43 +20,6 @@
 
 #include "sysfs.h"
 
-#define to_sattr(a) container_of(a,struct subsys_attribute, attr)
-
-/*
- * Subsystem file operations.
- * These operations allow subsystems to have files that can be 
- * read/written. 
- */
-static ssize_t 
-subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
-{
-	struct kset *kset = to_kset(kobj);
-	struct subsys_attribute * sattr = to_sattr(attr);
-	ssize_t ret = -EIO;
-
-	if (sattr->show)
-		ret = sattr->show(kset, page);
-	return ret;
-}
-
-static ssize_t 
-subsys_attr_store(struct kobject * kobj, struct attribute * attr, 
-		  const char * page, size_t count)
-{
-	struct kset *kset = to_kset(kobj);
-	struct subsys_attribute * sattr = to_sattr(attr);
-	ssize_t ret = -EIO;
-
-	if (sattr->store)
-		ret = sattr->store(kset, page, count);
-	return ret;
-}
-
-static struct sysfs_ops subsys_sysfs_ops = {
-	.show	= subsys_attr_show,
-	.store	= subsys_attr_store,
-};
-
 /*
  * There's one sysfs_buffer for each open file and one
  * sysfs_open_dirent for each sysfs_dirent with one or more open
@@ -66,7 +29,7 @@ static struct sysfs_ops subsys_sysfs_ops = {
  * sysfs_dirent->s_attr.open points to sysfs_open_dirent.  s_attr.open
  * is protected by sysfs_open_dirent_lock.
  */
-static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
 
 struct sysfs_open_dirent {
 	atomic_t		refcnt;
@@ -119,7 +82,11 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer
 
 	sysfs_put_active_two(attr_sd);
 
-	BUG_ON(count > (ssize_t)PAGE_SIZE);
+	/*
+	 * The code works fine with PAGE_SIZE return but it's likely to
+	 * indicate truncated result or overflow in normal use cases.
+	 */
+	BUG_ON(count >= (ssize_t)PAGE_SIZE);
 	if (count >= 0) {
 		buffer->needs_read_fill = 0;
 		buffer->count = count;
@@ -350,31 +317,23 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
 {
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
-	struct sysfs_buffer * buffer;
-	struct sysfs_ops * ops = NULL;
-	int error;
+	struct sysfs_buffer *buffer;
+	struct sysfs_ops *ops;
+	int error = -EACCES;
 
 	/* need attr_sd for attr and ops, its parent for kobj */
 	if (!sysfs_get_active_two(attr_sd))
 		return -ENODEV;
 
-	/* if the kobject has no ktype, then we assume that it is a subsystem
-	 * itself, and use ops for it.
-	 */
-	if (kobj->kset && kobj->kset->ktype)
-		ops = kobj->kset->ktype->sysfs_ops;
-	else if (kobj->ktype)
+	/* every kobject with an attribute needs a ktype assigned */
+	if (kobj->ktype && kobj->ktype->sysfs_ops)
 		ops = kobj->ktype->sysfs_ops;
-	else
-		ops = &subsys_sysfs_ops;
-
-	error = -EACCES;
-
-	/* No sysfs operations, either from having no subsystem,
-	 * or the subsystem have no operations.
-	 */
-	if (!ops)
+	else {
+		printk(KERN_ERR "missing sysfs attribute operations for "
+		       "kobject: %s\n", kobject_name(kobj));
+		WARN_ON(1);
 		goto err_out;
+	}
 
 	/* File needs write support.
 	 * The inode's perms must say it's ok, 
@@ -564,7 +523,11 @@ int sysfs_add_file_to_group(struct kobject *kobj,
 	struct sysfs_dirent *dir_sd;
 	int error;
 
-	dir_sd = sysfs_get_dirent(kobj->sd, group);
+	if (group)
+		dir_sd = sysfs_get_dirent(kobj->sd, group);
+	else
+		dir_sd = sysfs_get(kobj->sd);
+
 	if (!dir_sd)
 		return -ENOENT;
 
@@ -652,7 +615,10 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
 {
 	struct sysfs_dirent *dir_sd;
 
-	dir_sd = sysfs_get_dirent(kobj->sd, group);
+	if (group)
+		dir_sd = sysfs_get_dirent(kobj->sd, group);
+	else
+		dir_sd = sysfs_get(kobj->sd);
 	if (dir_sd) {
 		sysfs_hash_and_remove(dir_sd, attr->name);
 		sysfs_put(dir_sd);