1 files changed, 25 insertions, 59 deletions

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 27d1785b7644..a271c87c4472 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);