[PATCH 14/24] sysfs: In sysfs_chmod_file lazily propagate the mode change.

Eric W. Biederman
2009-05-28T23:07:50Z

From: Eric W. Biederman <ebiederm@xmission.com>

Now that sysfs_getattr and sysfs_permission refresh the vfs
inode there is no need to immediatly push the mode change
into the vfs cache. Reducing the amount of work needed and
simplifying the locking.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/sysfs/file.c | 31 ++++++++-----------------------
1 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 0786b41..31cfe1d 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -577,38 +577,23 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
*/
int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
{
- struct sysfs_dirent *victim_sd = NULL;
- struct dentry *victim = NULL;
- struct inode * inode;
+ struct sysfs_dirent *sd;
struct iattr newattrs;
int rc;

- rc = -ENOENT;
- victim_sd = sysfs_get_dirent(kobj->sd, attr->name);
- if (!victim_sd)
- goto out;
+ mutex_lock(&sysfs_mutex);

- mutex_lock(&sysfs_rename_mutex);
- victim = sysfs_get_dentry(victim_sd);
- mutex_unlock(&sysfs_rename_mutex);
- if (IS_ERR(victim)) {
- rc = PTR_ERR(victim);
- victim = NULL;
+ rc = -ENOENT;
+ sd = sysfs_find_dirent(kobj->sd, attr->name);
+ if (!sd)
goto out;
- }
-
- inode = victim->d_inode;

- mutex_lock(&inode->i_mutex);
-
- newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
+ newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE;
- rc = sysfs_setattr(victim, &newattrs);
+ rc = sysfs_sd_setattr(sd, &newattrs);

- mutex_unlock(&inode->i_mutex);
out:
- dput(victim);
- sysfs_put(victim_sd);
+ mutex_unlock(&sysfs_mutex);
return rc;
}
EXPORT_SYMBOL_GPL(sysfs_chmod_file);
--
1.6.3.1.54.g99dd.dirty