Message ID | 20200324141722.21308-1-ap420073@gmail.com |
---|---|
State | Changes Requested |
Delegated to: | David Miller |
Headers | show |
Series | [RESEND,net,1/3] class: add class_find_and_get_file_ns() helper function | expand |
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. And can you document what this function actually is in some kerneldoc? But, returning a kernfs_node from a driver core is _REALLY_ odd. Why do you need this and who cares about kernfs here? thanks, greg k-h
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
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; +} + static struct class *class_get(struct class *cls) { if (cls) @@ -580,6 +591,7 @@ int __init classes_init(void) EXPORT_SYMBOL_GPL(class_create_file_ns); EXPORT_SYMBOL_GPL(class_remove_file_ns); +EXPORT_SYMBOL_GPL(class_find_and_get_file_ns); EXPORT_SYMBOL_GPL(class_unregister); EXPORT_SYMBOL_GPL(class_destroy); diff --git a/include/linux/device/class.h b/include/linux/device/class.h index e8d470c457d1..230cf2ce6d3f 100644 --- a/include/linux/device/class.h +++ b/include/linux/device/class.h @@ -209,7 +209,9 @@ extern int __must_check class_create_file_ns(struct class *class, extern void class_remove_file_ns(struct class *class, const struct class_attribute *attr, const void *ns); - +struct kernfs_node *class_find_and_get_file_ns(struct class *cls, + const char *name, + const void *ns); static inline int __must_check class_create_file(struct class *class, const struct class_attribute *attr) {
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(-)