[PATCH] net: sysfs: Fix weird usage of class's namespace relevant fields

[Zijun Hu <zijun_hu@icloud.com>]

From: Zijun Hu <quic_zijuhu@quicinc.com>

Device class has two namespace relevant fields which are associated by
the following usage:

struct class {
	...
	const struct kobj_ns_type_operations *ns_type;
	const void *(*namespace)(const struct device *dev);
	...
}
if (dev->class && dev->class->ns_type)
	dev->class->namespace(dev);

The usage looks weird since it checks @ns_type but calls namespace()
it is found for all existing class definitions that the other filed is
also assigned once one is assigned in current kernel tree, so fix this
weird usage by checking @namespace to call namespace().

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
driver-core tree has similar fix as shown below:
https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/commit/?h=driver-core-next&id=a169a663bfa8198f33a5c1002634cc89e5128025
---
 net/core/net-sysfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 444f23e74f8e..d10c88f569b0 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1056,7 +1056,7 @@ static const void *rx_queue_namespace(const struct kobject *kobj)
 	struct device *dev = &queue->dev->dev;
 	const void *ns = NULL;
 
-	if (dev->class && dev->class->ns_type)
+	if (dev->class && dev->class->namespace)
 		ns = dev->class->namespace(dev);
 
 	return ns;
@@ -1740,7 +1740,7 @@ static const void *netdev_queue_namespace(const struct kobject *kobj)
 	struct device *dev = &queue->dev->dev;
 	const void *ns = NULL;
 
-	if (dev->class && dev->class->ns_type)
+	if (dev->class && dev->class->namespace)
 		ns = dev->class->namespace(dev);
 
 	return ns;

---
base-commit: 88fac17500f4ea49c7bac136cf1b27e7b9980075
change-id: 20240904-fix_class_ns-adf1ac05b6fc

Best regards,
-- 
Zijun Hu <quic_zijuhu@quicinc.com>