Messages in this thread | | | Date | Thu, 20 Feb 2020 20:51:49 +0100 | From | Christian Brauner <> | Subject | Re: [PATCH net-next v3 2/9] sysfs: add sysfs_link_change_owner() |
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On Thu, Feb 20, 2020 at 12:14:43PM +0100, Greg Kroah-Hartman wrote: > On Tue, Feb 18, 2020 at 05:29:36PM +0100, Christian Brauner wrote: > > Add a helper to change the owner of a sysfs link. > > This function will be used to correctly account for kobject ownership > > changes, e.g. when moving network devices between network namespaces. > > > > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> > > --- > > /* v2 */ > > - Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > > - Add comment how ownership of sysfs object is changed. > > > > /* v3 */ > > - Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > > - Add explicit uid/gid parameters. > > --- > > fs/sysfs/file.c | 40 ++++++++++++++++++++++++++++++++++++++++ > > include/linux/sysfs.h | 10 ++++++++++ > > 2 files changed, 50 insertions(+) > > > > diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c > > index 32bb04b4d9d9..df5107d7b3fd 100644 > > --- a/fs/sysfs/file.c > > +++ b/fs/sysfs/file.c > > @@ -570,6 +570,46 @@ static int internal_change_owner(struct kernfs_node *kn, struct kobject *kobj, > > return kernfs_setattr(kn, &newattrs); > > } > > > > +/** > > + * sysfs_link_change_owner - change owner of a link. > > + * @kobj: object of the kernfs_node the symlink is located in. > > + * @targ: object of the kernfs_node the symlink points to. > > + * @name: name of the link. > > + * @kuid: new owner's kuid > > + * @kgid: new owner's kgid > > + */ > > +int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, > > + const char *name, kuid_t kuid, kgid_t kgid) > > +{ > > + struct kernfs_node *parent, *kn = NULL; > > + int error; > > + > > + if (!kobj) > > + parent = sysfs_root_kn; > > + else > > + parent = kobj->sd; > > I don't understand this, why would (!kobj) ever be a valid situation?
Yeah, a caller could just pass in "sysfs_root_kn" itself if they for some reason needed to.
> > > + if (!targ->state_in_sysfs) > > + return -EINVAL; > > Should you also check kobj->state_in_sysfs as well?
Probably. I'll take a closer look now.
Thanks! Christian
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