[PATCH net-next 0/6] net: constify struct class usage

[PATCH net-next 0/6] net: constify struct class usage

[Ricardo B. Marliere]

This is a simple and straight forward cleanup series that aims to make the
class structures in net constant. This has been possible since 2023 [1].

[1]: https://lore.kernel.org/all/2023040248-customary-release-4aec@gregkh/

Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
Ricardo B. Marliere (6):
      net: hns: make hnae_class constant
      net: wan: framer: make framer_class constant
      net: ppp: make ppp_class constant
      net: wwan: hwsim: make wwan_hwsim_class constant
      net: wwan: core: make wwan_class constant
      nfc: core: make nfc_class constant

 drivers/net/ethernet/hisilicon/hns/hnae.c | 13 +++++++------
 drivers/net/ppp/ppp_generic.c             | 18 +++++++++---------
 drivers/net/wan/framer/framer-core.c      | 21 +++++++++------------
 drivers/net/wwan/wwan_core.c              | 30 +++++++++++++++---------------
 drivers/net/wwan/wwan_hwsim.c             | 16 ++++++++--------
 include/net/nfc/nfc.h                     |  2 +-
 net/nfc/core.c                            |  2 +-
 7 files changed, 50 insertions(+), 52 deletions(-)
---
base-commit: e960825709330cb199d209740326cec37e8c419d
change-id: 20240302-class_cleanup-net-next-e41dbdaf7f06

Best regards,
-- 
Ricardo B. Marliere <ricardo@marliere.net>

[PATCH net-next 1/6] net: hns: make hnae_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the hnae_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/ethernet/hisilicon/hns/hnae.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hnae.c b/drivers/net/ethernet/hisilicon/hns/hnae.c
index 8a1027ad340d..d4293f76d69d 100644
--- a/drivers/net/ethernet/hisilicon/hns/hnae.c
+++ b/drivers/net/ethernet/hisilicon/hns/hnae.c
@@ -12,7 +12,9 @@
 
 #define cls_to_ae_dev(dev) container_of(dev, struct hnae_ae_dev, cls_dev)
 
-static struct class *hnae_class;
+static const struct class hnae_class = {
+	.name = "hnae",
+};
 
 static void
 hnae_list_add(spinlock_t *lock, struct list_head *node, struct list_head *head)
@@ -111,7 +113,7 @@ static struct hnae_ae_dev *find_ae(const struct fwnode_handle *fwnode)
 
 	WARN_ON(!fwnode);
 
-	dev = class_find_device(hnae_class, NULL, fwnode, __ae_match);
+	dev = class_find_device(&hnae_class, NULL, fwnode, __ae_match);
 
 	return dev ? cls_to_ae_dev(dev) : NULL;
 }
@@ -415,7 +417,7 @@ int hnae_ae_register(struct hnae_ae_dev *hdev, struct module *owner)
 	hdev->owner = owner;
 	hdev->id = (int)atomic_inc_return(&id);
 	hdev->cls_dev.parent = hdev->dev;
-	hdev->cls_dev.class = hnae_class;
+	hdev->cls_dev.class = &hnae_class;
 	hdev->cls_dev.release = hnae_release;
 	(void)dev_set_name(&hdev->cls_dev, "hnae%d", hdev->id);
 	ret = device_register(&hdev->cls_dev);
@@ -448,13 +450,12 @@ EXPORT_SYMBOL(hnae_ae_unregister);
 
 static int __init hnae_init(void)
 {
-	hnae_class = class_create("hnae");
-	return PTR_ERR_OR_ZERO(hnae_class);
+	return class_register(&hnae_class);
 }
 
 static void __exit hnae_exit(void)
 {
-	class_destroy(hnae_class);
+	class_unregister(&hnae_class);
 }
 
 subsys_initcall(hnae_init);

-- 
2.43.0

Re: [PATCH net-next 1/6] net: hns: make hnae_class constant

[Simon Horman]

+ Benjamin Tissoires <benjamin.tissoires@redhat.com>

On Sat, Mar 02, 2024 at 02:05:57PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the hnae_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Simon Horman <horms@kernel.org>

> ---
>  drivers/net/ethernet/hisilicon/hns/hnae.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/hisilicon/hns/hnae.c b/drivers/net/ethernet/hisilicon/hns/hnae.c
> index 8a1027ad340d..d4293f76d69d 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hnae.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hnae.c
> @@ -12,7 +12,9 @@
>  
>  #define cls_to_ae_dev(dev) container_of(dev, struct hnae_ae_dev, cls_dev)
>  
> -static struct class *hnae_class;
> +static const struct class hnae_class = {
> +	.name = "hnae",
> +};
>  
>  static void
>  hnae_list_add(spinlock_t *lock, struct list_head *node, struct list_head *head)
> @@ -111,7 +113,7 @@ static struct hnae_ae_dev *find_ae(const struct fwnode_handle *fwnode)
>  
>  	WARN_ON(!fwnode);
>  
> -	dev = class_find_device(hnae_class, NULL, fwnode, __ae_match);
> +	dev = class_find_device(&hnae_class, NULL, fwnode, __ae_match);
>  
>  	return dev ? cls_to_ae_dev(dev) : NULL;
>  }
> @@ -415,7 +417,7 @@ int hnae_ae_register(struct hnae_ae_dev *hdev, struct module *owner)
>  	hdev->owner = owner;
>  	hdev->id = (int)atomic_inc_return(&id);
>  	hdev->cls_dev.parent = hdev->dev;
> -	hdev->cls_dev.class = hnae_class;
> +	hdev->cls_dev.class = &hnae_class;
>  	hdev->cls_dev.release = hnae_release;
>  	(void)dev_set_name(&hdev->cls_dev, "hnae%d", hdev->id);
>  	ret = device_register(&hdev->cls_dev);
> @@ -448,13 +450,12 @@ EXPORT_SYMBOL(hnae_ae_unregister);
>  
>  static int __init hnae_init(void)
>  {
> -	hnae_class = class_create("hnae");
> -	return PTR_ERR_OR_ZERO(hnae_class);
> +	return class_register(&hnae_class);
>  }
>  
>  static void __exit hnae_exit(void)
>  {
> -	class_destroy(hnae_class);
> +	class_unregister(&hnae_class);
>  }
>  
>  subsys_initcall(hnae_init);
> 
> -- 
> 2.43.0
> 
> 

[PATCH net-next 2/6] net: wan: framer: make framer_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the framer_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/wan/framer/framer-core.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/net/wan/framer/framer-core.c b/drivers/net/wan/framer/framer-core.c
index 33b358b99f70..f547c22e26ac 100644
--- a/drivers/net/wan/framer/framer-core.c
+++ b/drivers/net/wan/framer/framer-core.c
@@ -18,7 +18,12 @@
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
-static struct class *framer_class;
+static void framer_release(struct device *dev);
+static const struct class framer_class = {
+	.name = "framer",
+	.dev_release = framer_release,
+};
+
 static DEFINE_MUTEX(framer_provider_mutex);
 static LIST_HEAD(framer_provider_list);
 static DEFINE_IDA(framer_ida);
@@ -627,7 +632,7 @@ struct framer *framer_create(struct device *dev, struct device_node *node,
 	INIT_DELAYED_WORK(&framer->polling_work, framer_polling_work);
 	BLOCKING_INIT_NOTIFIER_HEAD(&framer->notifier_list);
 
-	framer->dev.class = framer_class;
+	framer->dev.class = &framer_class;
 	framer->dev.parent = dev;
 	framer->dev.of_node = node ? node : dev->of_node;
 	framer->id = id;
@@ -741,7 +746,7 @@ struct framer *framer_provider_simple_of_xlate(struct device *dev,
 	struct class_dev_iter iter;
 	struct framer *framer;
 
-	class_dev_iter_init(&iter, framer_class, NULL, NULL);
+	class_dev_iter_init(&iter, &framer_class, NULL, NULL);
 	while ((dev = class_dev_iter_next(&iter))) {
 		framer = dev_to_framer(dev);
 		if (args->np != framer->dev.of_node)
@@ -870,14 +875,6 @@ static void framer_release(struct device *dev)
 
 static int __init framer_core_init(void)
 {
-	framer_class = class_create("framer");
-	if (IS_ERR(framer_class)) {
-		pr_err("failed to create framer class (%pe)\n", framer_class);
-		return PTR_ERR(framer_class);
-	}
-
-	framer_class->dev_release = framer_release;
-
-	return 0;
+	return class_register(&framer_class);
 }
 device_initcall(framer_core_init);

-- 
2.43.0

Re: [PATCH net-next 2/6] net: wan: framer: make framer_class constant

[Simon Horman]

+ Herve Codina <herve.codina@bootlin.com>

On Sat, Mar 02, 2024 at 02:05:58PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the framer_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Simon Horman <horms@kernel.org>

> ---
>  drivers/net/wan/framer/framer-core.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/wan/framer/framer-core.c b/drivers/net/wan/framer/framer-core.c
> index 33b358b99f70..f547c22e26ac 100644
> --- a/drivers/net/wan/framer/framer-core.c
> +++ b/drivers/net/wan/framer/framer-core.c
> @@ -18,7 +18,12 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
>  
> -static struct class *framer_class;
> +static void framer_release(struct device *dev);
> +static const struct class framer_class = {
> +	.name = "framer",
> +	.dev_release = framer_release,
> +};
> +
>  static DEFINE_MUTEX(framer_provider_mutex);
>  static LIST_HEAD(framer_provider_list);
>  static DEFINE_IDA(framer_ida);
> @@ -627,7 +632,7 @@ struct framer *framer_create(struct device *dev, struct device_node *node,
>  	INIT_DELAYED_WORK(&framer->polling_work, framer_polling_work);
>  	BLOCKING_INIT_NOTIFIER_HEAD(&framer->notifier_list);
>  
> -	framer->dev.class = framer_class;
> +	framer->dev.class = &framer_class;
>  	framer->dev.parent = dev;
>  	framer->dev.of_node = node ? node : dev->of_node;
>  	framer->id = id;
> @@ -741,7 +746,7 @@ struct framer *framer_provider_simple_of_xlate(struct device *dev,
>  	struct class_dev_iter iter;
>  	struct framer *framer;
>  
> -	class_dev_iter_init(&iter, framer_class, NULL, NULL);
> +	class_dev_iter_init(&iter, &framer_class, NULL, NULL);
>  	while ((dev = class_dev_iter_next(&iter))) {
>  		framer = dev_to_framer(dev);
>  		if (args->np != framer->dev.of_node)
> @@ -870,14 +875,6 @@ static void framer_release(struct device *dev)
>  
>  static int __init framer_core_init(void)
>  {
> -	framer_class = class_create("framer");
> -	if (IS_ERR(framer_class)) {
> -		pr_err("failed to create framer class (%pe)\n", framer_class);
> -		return PTR_ERR(framer_class);
> -	}
> -
> -	framer_class->dev_release = framer_release;
> -
> -	return 0;
> +	return class_register(&framer_class);
>  }
>  device_initcall(framer_core_init);
> 
> -- 
> 2.43.0
> 
> 

Re: [PATCH net-next 2/6] net: wan: framer: make framer_class constant

[Herve Codina]

Hi,

On Mon, 4 Mar 2024 17:52:46 +0000
Simon Horman <horms@kernel.org> wrote:

> + Herve Codina <herve.codina@bootlin.com>
> 
> On Sat, Mar 02, 2024 at 02:05:58PM -0300, Ricardo B. Marliere wrote:
> > Since commit 43a7206b0963 ("driver core: class: make class_register() take
> > a const *"), the driver core allows for struct class to be in read-only
> > memory, so move the framer_class structure to be declared at build time
> > placing it into read-only memory, instead of having to be dynamically
> > allocated at boot time.
> > 
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
> 
> Reviewed-by: Simon Horman <horms@kernel.org>
> 

Thanks for the patch.

Acked-by: Herve Codina <herve.codina@bootlin.com>

Best regards,
Hervé

[PATCH net-next 3/6] net: ppp: make ppp_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the ppp_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/ppp/ppp_generic.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index db1d11ae817b..fe380fe196e7 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -295,7 +295,9 @@ static void ppp_setup(struct net_device *dev);
 
 static const struct net_device_ops ppp_netdev_ops;
 
-static struct class *ppp_class;
+static const struct class ppp_class = {
+	.name = "ppp",
+};
 
 /* per net-namespace data */
 static inline struct ppp_net *ppp_pernet(struct net *net)
@@ -1394,11 +1396,9 @@ static int __init ppp_init(void)
 		goto out_net;
 	}
 
-	ppp_class = class_create("ppp");
-	if (IS_ERR(ppp_class)) {
-		err = PTR_ERR(ppp_class);
+	err = class_register(&ppp_class);
+	if (err)
 		goto out_chrdev;
-	}
 
 	err = rtnl_link_register(&ppp_link_ops);
 	if (err) {
@@ -1407,12 +1407,12 @@ static int __init ppp_init(void)
 	}
 
 	/* not a big deal if we fail here :-) */
-	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
+	device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 
 	return 0;
 
 out_class:
-	class_destroy(ppp_class);
+	class_unregister(&ppp_class);
 out_chrdev:
 	unregister_chrdev(PPP_MAJOR, "ppp");
 out_net:
@@ -3549,8 +3549,8 @@ static void __exit ppp_cleanup(void)
 		pr_err("PPP: removing module but units remain!\n");
 	rtnl_link_unregister(&ppp_link_ops);
 	unregister_chrdev(PPP_MAJOR, "ppp");
-	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
-	class_destroy(ppp_class);
+	device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0));
+	class_unregister(&ppp_class);
 	unregister_pernet_device(&ppp_net_ops);
 }
 

-- 
2.43.0

Re: [PATCH net-next 3/6] net: ppp: make ppp_class constant

[Simon Horman]

On Sat, Mar 02, 2024 at 02:05:59PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the ppp_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next 3/6] net: ppp: make ppp_class constant

[Breno Leitao]

On Sat, Mar 02, 2024 at 02:05:59PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the ppp_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviwed-by: Breno Leitao <leitao@debian.org>

[PATCH net-next 4/6] net: wwan: hwsim: make wwan_hwsim_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the wwan_hwsim_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/wwan/wwan_hwsim.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wwan/wwan_hwsim.c b/drivers/net/wwan/wwan_hwsim.c
index ff3dd24ddb33..b02befd1b6fb 100644
--- a/drivers/net/wwan/wwan_hwsim.c
+++ b/drivers/net/wwan/wwan_hwsim.c
@@ -25,7 +25,9 @@ static int wwan_hwsim_devsnum = 2;
 module_param_named(devices, wwan_hwsim_devsnum, int, 0444);
 MODULE_PARM_DESC(devices, "Number of simulated devices");
 
-static struct class *wwan_hwsim_class;
+static const struct class wwan_hwsim_class = {
+	.name = "wwan_hwsim",
+};
 
 static struct dentry *wwan_hwsim_debugfs_topdir;
 static struct dentry *wwan_hwsim_debugfs_devcreate;
@@ -277,7 +279,7 @@ static struct wwan_hwsim_dev *wwan_hwsim_dev_new(void)
 	spin_unlock(&wwan_hwsim_devs_lock);
 
 	dev->dev.release = wwan_hwsim_dev_release;
-	dev->dev.class = wwan_hwsim_class;
+	dev->dev.class = &wwan_hwsim_class;
 	dev_set_name(&dev->dev, "hwsim%u", dev->id);
 
 	spin_lock_init(&dev->ports_lock);
@@ -511,11 +513,9 @@ static int __init wwan_hwsim_init(void)
 	if (!wwan_wq)
 		return -ENOMEM;
 
-	wwan_hwsim_class = class_create("wwan_hwsim");
-	if (IS_ERR(wwan_hwsim_class)) {
-		err = PTR_ERR(wwan_hwsim_class);
+	err = class_register(&wwan_hwsim_class);
+	if (err)
 		goto err_wq_destroy;
-	}
 
 	wwan_hwsim_debugfs_topdir = debugfs_create_dir("wwan_hwsim", NULL);
 	wwan_hwsim_debugfs_devcreate =
@@ -534,7 +534,7 @@ static int __init wwan_hwsim_init(void)
 	wwan_hwsim_free_devs();
 	flush_workqueue(wwan_wq);	/* Wait deletion works completion */
 	debugfs_remove(wwan_hwsim_debugfs_topdir);
-	class_destroy(wwan_hwsim_class);
+	class_unregister(&wwan_hwsim_class);
 err_wq_destroy:
 	destroy_workqueue(wwan_wq);
 
@@ -547,7 +547,7 @@ static void __exit wwan_hwsim_exit(void)
 	wwan_hwsim_free_devs();
 	flush_workqueue(wwan_wq);	/* Wait deletion works completion */
 	debugfs_remove(wwan_hwsim_debugfs_topdir);
-	class_destroy(wwan_hwsim_class);
+	class_unregister(&wwan_hwsim_class);
 	destroy_workqueue(wwan_wq);
 }
 

-- 
2.43.0

[PATCH net-next 5/6] net: wwan: core: make wwan_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the wwan_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/wwan/wwan_core.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index b0030f3ed0f0..17431f1b1a0c 100644
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -26,7 +26,9 @@
 static DEFINE_MUTEX(wwan_register_lock); /* WWAN device create|remove lock */
 static DEFINE_IDA(minors); /* minors for WWAN port chardevs */
 static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */
-static struct class *wwan_class;
+static const struct class wwan_class = {
+	.name = "wwan",
+};
 static int wwan_major;
 static struct dentry *wwan_debugfs_dir;
 
@@ -130,7 +132,7 @@ static struct wwan_device *wwan_dev_get_by_parent(struct device *parent)
 {
 	struct device *dev;
 
-	dev = class_find_device(wwan_class, NULL, parent, wwan_dev_parent_match);
+	dev = class_find_device(&wwan_class, NULL, parent, wwan_dev_parent_match);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -147,7 +149,7 @@ static struct wwan_device *wwan_dev_get_by_name(const char *name)
 {
 	struct device *dev;
 
-	dev = class_find_device(wwan_class, NULL, name, wwan_dev_name_match);
+	dev = class_find_device(&wwan_class, NULL, name, wwan_dev_name_match);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -183,7 +185,7 @@ static struct wwan_device *wwan_dev_get_by_debugfs(struct dentry *dir)
 {
 	struct device *dev;
 
-	dev = class_find_device(wwan_class, NULL, dir, wwan_dev_debugfs_match);
+	dev = class_find_device(&wwan_class, NULL, dir, wwan_dev_debugfs_match);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -239,7 +241,7 @@ static struct wwan_device *wwan_create_dev(struct device *parent)
 	}
 
 	wwandev->dev.parent = parent;
-	wwandev->dev.class = wwan_class;
+	wwandev->dev.class = &wwan_class;
 	wwandev->dev.type = &wwan_dev_type;
 	wwandev->id = id;
 	dev_set_name(&wwandev->dev, "wwan%d", wwandev->id);
@@ -265,7 +267,7 @@ static struct wwan_device *wwan_create_dev(struct device *parent)
 
 static int is_wwan_child(struct device *dev, void *data)
 {
-	return dev->class == wwan_class;
+	return dev->class == &wwan_class;
 }
 
 static void wwan_remove_dev(struct wwan_device *wwandev)
@@ -375,7 +377,7 @@ static struct wwan_port *wwan_port_get_by_minor(unsigned int minor)
 {
 	struct device *dev;
 
-	dev = class_find_device(wwan_class, NULL, &minor, wwan_port_minor_match);
+	dev = class_find_device(&wwan_class, NULL, &minor, wwan_port_minor_match);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -405,7 +407,7 @@ static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt)
 		return -ENOMEM;
 
 	/* Collect ids of same name format ports */
-	class_dev_iter_init(&iter, wwan_class, NULL, &wwan_port_dev_type);
+	class_dev_iter_init(&iter, &wwan_class, NULL, &wwan_port_dev_type);
 	while ((dev = class_dev_iter_next(&iter))) {
 		if (dev->parent != &wwandev->dev)
 			continue;
@@ -477,7 +479,7 @@ struct wwan_port *wwan_create_port(struct device *parent,
 	mutex_init(&port->data_lock);
 
 	port->dev.parent = &wwandev->dev;
-	port->dev.class = wwan_class;
+	port->dev.class = &wwan_class;
 	port->dev.type = &wwan_port_dev_type;
 	port->dev.devt = MKDEV(wwan_major, minor);
 	dev_set_drvdata(&port->dev, drvdata);
@@ -1212,11 +1214,9 @@ static int __init wwan_init(void)
 	if (err)
 		return err;
 
-	wwan_class = class_create("wwan");
-	if (IS_ERR(wwan_class)) {
-		err = PTR_ERR(wwan_class);
+	err = class_register(&wwan_class);
+	if (err)
 		goto unregister;
-	}
 
 	/* chrdev used for wwan ports */
 	wwan_major = __register_chrdev(0, 0, WWAN_MAX_MINORS, "wwan_port",
@@ -1233,7 +1233,7 @@ static int __init wwan_init(void)
 	return 0;
 
 destroy:
-	class_destroy(wwan_class);
+	class_unregister(&wwan_class);
 unregister:
 	rtnl_link_unregister(&wwan_rtnl_link_ops);
 	return err;
@@ -1244,7 +1244,7 @@ static void __exit wwan_exit(void)
 	debugfs_remove_recursive(wwan_debugfs_dir);
 	__unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port");
 	rtnl_link_unregister(&wwan_rtnl_link_ops);
-	class_destroy(wwan_class);
+	class_unregister(&wwan_class);
 }
 
 module_init(wwan_init);

-- 
2.43.0

[PATCH net-next 6/6] nfc: core: make nfc_class constant

[Ricardo B. Marliere]

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the nfc_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 include/net/nfc/nfc.h | 2 +-
 net/nfc/core.c        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/net/nfc/nfc.h b/include/net/nfc/nfc.h
index 5dee575fbe86..3d07abacf08b 100644
--- a/include/net/nfc/nfc.h
+++ b/include/net/nfc/nfc.h
@@ -196,7 +196,7 @@ struct nfc_dev {
 };
 #define to_nfc_dev(_dev) container_of(_dev, struct nfc_dev, dev)
 
-extern struct class nfc_class;
+extern const struct class nfc_class;
 
 struct nfc_dev *nfc_allocate_device(const struct nfc_ops *ops,
 				    u32 supported_protocols,
diff --git a/net/nfc/core.c b/net/nfc/core.c
index eb2c0959e5b6..e58dc6405054 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -1015,7 +1015,7 @@ static void nfc_check_pres_timeout(struct timer_list *t)
 	schedule_work(&dev->check_pres_work);
 }
 
-struct class nfc_class = {
+const struct class nfc_class = {
 	.name = "nfc",
 	.dev_release = nfc_release,
 };

-- 
2.43.0

Re: [PATCH net-next 6/6] nfc: core: make nfc_class constant

[Simon Horman]

On Sat, Mar 02, 2024 at 02:06:02PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the nfc_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next 6/6] nfc: core: make nfc_class constant

[Breno Leitao]

On Sat, Mar 02, 2024 at 02:06:02PM -0300, Ricardo B. Marliere wrote:
> Since commit 43a7206b0963 ("driver core: class: make class_register() take
> a const *"), the driver core allows for struct class to be in read-only
> memory, so move the nfc_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviwed-by: Breno Leitao <leitao@debian.org>

Re: [PATCH net-next 0/6] net: constify struct class usage

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sat, 02 Mar 2024 14:05:56 -0300 you wrote:
> This is a simple and straight forward cleanup series that aims to make the
> class structures in net constant. This has been possible since 2023 [1].
> 
> [1]: https://lore.kernel.org/all/2023040248-customary-release-4aec@gregkh/
> 
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
> 
> [...]

Here is the summary with links:
  - [net-next,1/6] net: hns: make hnae_class constant
    https://git.kernel.org/netdev/net-next/c/b6e3c115efb5
  - [net-next,2/6] net: wan: framer: make framer_class constant
    https://git.kernel.org/netdev/net-next/c/63767a76318c
  - [net-next,3/6] net: ppp: make ppp_class constant
    https://git.kernel.org/netdev/net-next/c/2ad2018aa357
  - [net-next,4/6] net: wwan: hwsim: make wwan_hwsim_class constant
    https://git.kernel.org/netdev/net-next/c/d9567f212b15
  - [net-next,5/6] net: wwan: core: make wwan_class constant
    https://git.kernel.org/netdev/net-next/c/070bef83f03e
  - [net-next,6/6] nfc: core: make nfc_class constant
    https://git.kernel.org/netdev/net-next/c/e55600116929

You are awesome, thank you!
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