sysfs: kill unnecessary attribute->owner
sysfs is now completely out of driver/module lifetime game. After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners. Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.
This patch kills now unnecessary attribute->owner. Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.
For more info regarding lifetime rule cleanup, please read the
following message.
http://article.gmane.org/gmane.linux.kernel/510293
(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index d673d9b..a84b734 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -241,7 +241,6 @@
static int sysfs_open_file(struct inode *inode, struct file *file)
{
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- struct attribute *attr = attr_sd->s_elem.attr.attr;
struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj;
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
@@ -251,11 +250,6 @@
if (!sysfs_get_active_two(attr_sd))
return -ENODEV;
- /* Grab the module reference for this attribute */
- error = -ENODEV;
- if (!try_module_get(attr->owner))
- goto err_sput;
-
/* if the kobject has no ktype, then we assume that it is a subsystem
* itself, and use ops for it.
*/
@@ -272,7 +266,7 @@
* or the subsystem have no operations.
*/
if (!ops)
- goto err_mput;
+ goto err_out;
/* File needs write support.
* The inode's perms must say it's ok,
@@ -280,7 +274,7 @@
*/
if (file->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO) || !ops->store)
- goto err_mput;
+ goto err_out;
}
/* File needs read support.
@@ -289,7 +283,7 @@
*/
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO) || !ops->show)
- goto err_mput;
+ goto err_out;
}
/* No error? Great, allocate a buffer for the file, and store it
@@ -298,7 +292,7 @@
error = -ENOMEM;
buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
if (!buffer)
- goto err_mput;
+ goto err_out;
init_MUTEX(&buffer->sem);
buffer->needs_read_fill = 1;
@@ -310,9 +304,7 @@
sysfs_get(attr_sd);
return 0;
- err_mput:
- module_put(attr->owner);
- err_sput:
+ err_out:
sysfs_put_active_two(attr_sd);
return error;
}
@@ -320,12 +312,9 @@
static int sysfs_release(struct inode * inode, struct file * filp)
{
struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
- struct attribute *attr = attr_sd->s_elem.attr.attr;
struct sysfs_buffer *buffer = filp->private_data;
sysfs_put(attr_sd);
- /* After this point, attr should not be accessed. */
- module_put(attr->owner);
if (buffer) {
if (buffer->page)