Re: [PATCH 2.6.18] sysfs: remove duplicated dput in sysfs_update_file

From: Maneesh Soni
Date: Wed Sep 20 2006 - 23:24:37 EST


On Wed, Sep 20, 2006 at 04:38:00PM +0900, Hidetoshi Seto wrote:
> 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>
>
> ---
> fs/sysfs/file.c | 5 -----
> 1 files changed, 5 deletions(-)
>
> Index: linux-2.6.18/fs/sysfs/file.c
> ===================================================================
> --- linux-2.6.18.orig/fs/sysfs/file.c
> +++ linux-2.6.18/fs/sysfs/file.c
> @@ -483,11 +483,6 @@
> (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);
>
> -
>

Looks good to me..

Thanks
Maneesh
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