sysfs: remove duplicated dput in sysfs_update_file

From: Hidetoshi Seto
Date: Wed Sep 20 2006 - 03:38:00 EST


Following function can drops d_count twice against one reference
by lookup_one_len.

<SOURCE>
/**
* sysfs_update_file - update the modified timestamp on an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
*/
int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
{
struct dentry * dir = kobj->dentry;
struct dentry * victim;
int res = -ENOENT;

mutex_lock(&dir->d_inode->i_mutex);
victim = lookup_one_len(attr->name, dir, strlen(attr->name));
if (!IS_ERR(victim)) {
/* make sure dentry is really there */
if (victim->d_inode &&
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
fsnotify_modify(victim);

/**
* Drop reference from initial sysfs_get_dentry().
*/
dput(victim);
res = 0;
} else
d_drop(victim);

/**
* Drop the reference acquired from sysfs_get_dentry() above.
*/
dput(victim);
}
mutex_unlock(&dir->d_inode->i_mutex);

return res;
}
</SOURCE>

PCI-hotplug (drivers/pci/hotplug/pci_hotplug_core.c) is only user of
this function. I confirmed that dentry of /sys/bus/pci/slots/XXX/*
have negative d_count value.

This patch removes unnecessary dput().

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Acked-by: Maneesh Soni <maneesh@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
fs/sysfs/file.c | 5 -----
1 file changed, 5 deletions(-)

--- gregkh-2.6.orig/fs/sysfs/file.c
+++ gregkh-2.6/fs/sysfs/file.c
@@ -497,11 +497,6 @@ int sysfs_update_file(struct kobject * k
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
fsnotify_modify(victim);
-
- /**
- * Drop reference from initial sysfs_get_dentry().
- */
- dput(victim);
res = 0;
} else
d_drop(victim);


Patches currently in gregkh-2.6 which might be from seto.hidetoshi@xxxxxxxxxxxxxx are

driver/sysfs-remove-duplicated-dput-in-sysfs_update_file.patch
driver/sysfs-update-obsolete-comment-in-sysfs_update_file.patch
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