sysfs: kill unnecessary sysfs_get() in open paths

There's no reason to get an extra reference to sysfs_dirent for an
open file.  Open file has a reference to the dentry which in turn has
a reference to sysfs_dirent.  This is fairly obvious as otherwise open
itself won't be able to access the sysfs_dirent.  Kill the extra
sysfs_get() and matching sysfs_put().
Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/bin.c

@@ -193,9 +193,8 @@ static int open(struct inode * inode, struct file * file)
 	mutex_init(&bb->mutex);
 	file->private_data = bb;
 
-	/* open succeeded, put active reference and pin attr_sd */
+	/* open succeeded, put active reference */
 	sysfs_put_active(attr_sd);
-	sysfs_get(attr_sd);
 	return 0;
 
  err_out:
@@ -211,7 +210,6 @@ static int release(struct inode * inode, struct file * file)
 
 	if (bb->mmapped)
 		sysfs_put_active_two(attr_sd);
-	sysfs_put(attr_sd);
 	kfree(bb->buffer);
 	kfree(bb);
 	return 0;

fs/sysfs/file.c

@@ -298,9 +298,8 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
 	buffer->ops = ops;
 	file->private_data = buffer;
 
-	/* open succeeded, put active references and pin attr_sd */
+	/* open succeeded, put active references */
 	sysfs_put_active_two(attr_sd);
-	sysfs_get(attr_sd);
 	return 0;
 
  err_out:
@@ -310,11 +309,8 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
 
 static int sysfs_release(struct inode * inode, struct file * filp)
 {
-	struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
 	struct sysfs_buffer *buffer = filp->private_data;
 
-	sysfs_put(attr_sd);
-
 	if (buffer) {
 		if (buffer->page)
 			free_page((unsigned long)buffer->page);