5 files changed, 48 insertions, 14 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 49bd219275db..9ee956864445 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -50,6 +50,32 @@ static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
         return sd;
 }
 
+/**
+ *
+ * Return -EEXIST if there is already a sysfs element with the same name for
+ * the same parent.
+ *
+ * called with parent inode's i_mutex held
+ */
+int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
+                          const unsigned char *new)
+{
+        struct sysfs_dirent * sd;
+
+        list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+                if (sd->s_element) {
+                        const unsigned char *existing = sysfs_get_name(sd);
+                        if (strcmp(existing, new))
+                                continue;
+                        else
+                                return -EEXIST;
+                }
+        }
+
+        return 0;
+}
+
+
 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
                         void * element, umode_t mode, int type)
 {
@@ -102,7 +128,11 @@ static int create_dir(struct kobject * k, struct dentry * p,
         mutex_lock(&p->d_inode->i_mutex);
         *d = lookup_one_len(n, p, strlen(n));
         if (!IS_ERR(*d)) {
-                error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
+                if (sysfs_dirent_exist(p->d_fsdata, n))
+                        error = -EEXIST;
+                else
+                        error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
+                                                                SYSFS_DIR);
                 if (!error) {
                         error = sysfs_create(*d, mode, init_dir);
                         if (!error) {
@@ -302,6 +332,7 @@ void sysfs_remove_dir(struct kobject * kobj)
          * Drop reference from dget() on entrance.
          */
         dput(dentry);
+        kobj->dentry = NULL;
 }
 
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
@@ -479,7 +510,3 @@ struct file_operations sysfs_dir_operations = {
         .read           = generic_read_dir,
         .readdir        = sysfs_readdir,
 };
-
-EXPORT_SYMBOL_GPL(sysfs_create_dir);
-EXPORT_SYMBOL_GPL(sysfs_remove_dir);
-EXPORT_SYMBOL_GPL(sysfs_rename_dir);
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index d0e3d8495165..5e83e7246788 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -301,9 +301,8 @@ static int check_perm(struct inode * inode, struct file * file)
         /* No error? Great, allocate a buffer for the file, and store it
          * it in file->private_data for easy access.
          */
-        buffer = kmalloc(sizeof(struct sysfs_buffer),GFP_KERNEL);
+        buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
         if (buffer) {
-                memset(buffer,0,sizeof(struct sysfs_buffer));
                 init_MUTEX(&buffer->sem);
                 buffer->needs_read_fill = 1;
                 buffer->ops = ops;
@@ -362,10 +361,12 @@ int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type)
 {
         struct sysfs_dirent * parent_sd = dir->d_fsdata;
         umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
-        int error = 0;
+        int error = -EEXIST;
 
         mutex_lock(&dir->d_inode->i_mutex);
-        error = sysfs_make_dirent(parent_sd, NULL, (void *) attr, mode, type);
+        if (!sysfs_dirent_exist(parent_sd, attr->name))
+                error = sysfs_make_dirent(parent_sd, NULL, (void *)attr,
+                                          mode, type);
         mutex_unlock(&dir->d_inode->i_mutex);
 
         return error;
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 689f7bcfaf30..4c29ac41ac3e 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -54,11 +54,10 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
 
         if (!sd_iattr) {
                 /* setting attributes for the first time, allocate now */
-                sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
+                sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
                 if (!sd_iattr)
                         return -ENOMEM;
                 /* assign default attributes */
-                memset(sd_iattr, 0, sizeof(struct iattr));
                 sd_iattr->ia_mode = sd->s_mode;
                 sd_iattr->ia_uid = 0;
                 sd_iattr->ia_gid = 0;
@@ -227,12 +226,16 @@ void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
 void sysfs_hash_and_remove(struct dentry * dir, const char * name)
 {
         struct sysfs_dirent * sd;
-        struct sysfs_dirent * parent_sd = dir->d_fsdata;
+        struct sysfs_dirent * parent_sd;
+
+        if (!dir)
+                return;
 
         if (dir->d_inode == NULL)
                 /* no inode means this hasn't been made visible yet */
                 return;
 
+        parent_sd = dir->d_fsdata;
         mutex_lock(&dir->d_inode->i_mutex);
         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
                 if (!sd->s_element)
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index e38d6338a20d..d2eac3ceed5f 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -66,6 +66,7 @@ static int sysfs_add_link(struct dentry * parent, const char * name, struct kobj
         if (!error)
                 return 0;
 
+        kobject_put(target);
         kfree(sl->link_name);
 exit2:
         kfree(sl);
@@ -82,12 +83,13 @@ exit1:
 int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name)
 {
         struct dentry * dentry = kobj->dentry;
-        int error = 0;
+        int error = -EEXIST;
 
         BUG_ON(!kobj || !kobj->dentry || !name);
 
         mutex_lock(&dentry->d_inode->i_mutex);
-        error = sysfs_add_link(dentry, name, target);
+        if (!sysfs_dirent_exist(dentry->d_fsdata, name))
+                error = sysfs_add_link(dentry, name, target);
         mutex_unlock(&dentry->d_inode->i_mutex);
         return error;
 }
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 3f8953e0e5d0..cf11d5b789d9 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -5,6 +5,7 @@ extern kmem_cache_t *sysfs_dir_cachep;
 extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
 extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *));
 
+extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *);
 extern int sysfs_make_dirent(struct sysfs_dirent *, struct dentry *, void *,
                                 umode_t, int);