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: [email protected]
Fixes: b76cdba9cdb2 ("[PATCH] bonding: add sysfs functionality to bonding (large)")
Signed-off-by: Taehee Yoo <[email protected]>
---
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;
+}
+
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)
{
--
2.17.1
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: [email protected]
> Fixes: b76cdba9cdb2 ("[PATCH] bonding: add sysfs functionality to bonding (large)")
> Signed-off-by: Taehee Yoo <[email protected]>
> ---
> 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 <[email protected]> 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: [email protected]
> > Fixes: b76cdba9cdb2 ("[PATCH] bonding: add sysfs functionality to bonding (large)")
> > Signed-off-by: Taehee Yoo <[email protected]>
> > ---
> > 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