Messages in this thread | | | From | Taehee Yoo <> | Date | Wed, 25 Mar 2020 01:28:18 +0900 | Subject | Re: [PATCH RESEND net 1/3] class: add class_find_and_get_file_ns() helper function |
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On Wed, 25 Mar 2020 at 00:44, Greg KH <gregkh@linuxfoundation.org> wrote: >
Hi Greg, Thank you for the review!
> On Tue, Mar 24, 2020 at 02:17:22PM +0000, Taehee Yoo wrote: > > The new helper function is to find and get a class file. > > This function is useful for checking whether the class file is existing > > or not. This function will be used by networking stack to > > check "/sys/class/net/*" file. > > > > Reported-by: syzbot+830c6dbfc71edc4f0b8f@syzkaller.appspotmail.com > > Fixes: b76cdba9cdb2 ("[PATCH] bonding: add sysfs functionality to bonding (large)") > > Signed-off-by: Taehee Yoo <ap420073@gmail.com> > > --- > > drivers/base/class.c | 12 ++++++++++++ > > include/linux/device/class.h | 4 +++- > > 2 files changed, 15 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/base/class.c b/drivers/base/class.c > > index bcd410e6d70a..dedf41f32f0d 100644 > > --- a/drivers/base/class.c > > +++ b/drivers/base/class.c > > @@ -105,6 +105,17 @@ void class_remove_file_ns(struct class *cls, const struct class_attribute *attr, > > sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns); > > } > > > > +struct kernfs_node *class_find_and_get_file_ns(struct class *cls, > > + const char *name, > > + const void *ns) > > +{ > > + struct kernfs_node *kn = NULL; > > + > > + if (cls) > > + kn = kernfs_find_and_get_ns(cls->p->subsys.kobj.sd, name, ns); > > + return kn; > > +} > > + > > You can put the EXPORT_SYMBOL_GPL() under here. >
Okay, I will change this.
> And can you document what this function actually is in some kerneldoc? >
Thanks, I will add some kernel-doc comment.
> But, returning a kernfs_node from a driver core is _REALLY_ odd. Why do > you need this and who cares about kernfs here? >
I fully agree with that. My previous version of this function was here:
bool class_has_file_ns(struct class *cls, const char *name, const void *ns) { struct kernfs_node *kn = NULL;
if (cls) { kn = kernfs_find_and_get_ns(cls->p->subsys.kobj.sd, name, ns); if (kn) { kernfs_put(kn); return true; } } return false; }
I wanted this function could be used in general cases. But I thought this function couldn't be used in general cases. So, I made class_find_and_get_file_ns() but I couldn't find a more appropriate return type. I think I'd rather to use class_has_file_ns() instead of class_find_and_get_file_ns() because of an awkward return type. How do you think about it?
> thanks, > > greg k-h
Thanks a lot, Taehee Yoo
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