[PATCH 1/9] bsr: make bsr_class a static const structure

[PATCH 1/9] bsr: make bsr_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the bsr_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: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/bsr.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/char/bsr.c b/drivers/char/bsr.c
index ff429ba02fa4..0654f0e6b320 100644
--- a/drivers/char/bsr.c
+++ b/drivers/char/bsr.c
@@ -61,7 +61,6 @@ struct bsr_dev {
 
 static unsigned total_bsr_devs;
 static LIST_HEAD(bsr_devs);
-static struct class *bsr_class;
 static int bsr_major;
 
 enum {
@@ -108,6 +107,11 @@ static struct attribute *bsr_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(bsr_dev);
 
+static const struct class bsr_class = {
+	.name		= "bsr",
+	.dev_groups	= bsr_dev_groups,
+};
+
 static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	unsigned long size   = vma->vm_end - vma->vm_start;
@@ -244,7 +248,7 @@ static int bsr_add_node(struct device_node *bn)
 			goto out_err;
 		}
 
-		cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
+		cur->bsr_device = device_create(&bsr_class, NULL, cur->bsr_dev,
 						cur, "%s", cur->bsr_name);
 		if (IS_ERR(cur->bsr_device)) {
 			printk(KERN_ERR "device_create failed for %s\n",
@@ -293,13 +297,9 @@ static int __init bsr_init(void)
 	if (!np)
 		goto out_err;
 
-	bsr_class = class_create("bsr");
-	if (IS_ERR(bsr_class)) {
-		printk(KERN_ERR "class_create() failed for bsr_class\n");
-		ret = PTR_ERR(bsr_class);
+	ret = class_register(&bsr_class);
+	if (err)
 		goto out_err_1;
-	}
-	bsr_class->dev_groups = bsr_dev_groups;
 
 	ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
 	bsr_major = MAJOR(bsr_dev);
@@ -320,7 +320,7 @@ static int __init bsr_init(void)
 	unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
 
  out_err_2:
-	class_destroy(bsr_class);
+	class_unregister(&bsr_class);
 
  out_err_1:
 	of_node_put(np);
@@ -335,8 +335,7 @@ static void __exit  bsr_exit(void)
 
 	bsr_cleanup_devs();
 
-	if (bsr_class)
-		class_destroy(bsr_class);
+	class_unregister(&bsr_class);
 
 	if (bsr_major)
 		unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
-- 
2.41.0

[PATCH 2/9] dsp56k: make dsp56k_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the dsp56k_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: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/dsp56k.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index b3eaf3e5ef2e..bda27e595da1 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -101,7 +101,9 @@ static struct dsp56k_device {
 	int tx_wsize, rx_wsize;
 } dsp56k;
 
-static struct class *dsp56k_class;
+static const struct class dsp56k_class = {
+	.name = "dsp56k",
+};
 
 static int dsp56k_reset(void)
 {
@@ -493,7 +495,7 @@ static const char banner[] __initconst = KERN_INFO "DSP56k driver installed\n";
 
 static int __init dsp56k_init_driver(void)
 {
-	int err = 0;
+	int err;
 
 	if(!MACH_IS_ATARI || !ATARIHW_PRESENT(DSP56K)) {
 		printk("DSP56k driver: Hardware not present\n");
@@ -504,12 +506,10 @@ static int __init dsp56k_init_driver(void)
 		printk("DSP56k driver: Unable to register driver\n");
 		return -ENODEV;
 	}
-	dsp56k_class = class_create("dsp56k");
-	if (IS_ERR(dsp56k_class)) {
-		err = PTR_ERR(dsp56k_class);
+	err = class_register(&dsp56k_class);
+	if (err)
 		goto out_chrdev;
-	}
-	device_create(dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
+	device_create(&dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
 		      "dsp56k");
 
 	printk(banner);
@@ -524,8 +524,8 @@ module_init(dsp56k_init_driver);
 
 static void __exit dsp56k_cleanup_driver(void)
 {
-	device_destroy(dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
-	class_destroy(dsp56k_class);
+	device_destroy(&dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
+	class_unregister(&dsp56k_class);
 	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
 }
 module_exit(dsp56k_cleanup_driver);
-- 
2.41.0

[PATCH 3/9] char: lp: make lp_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the lp_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/lp.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 70cfc5140c2c..2f171d14b9b5 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -145,7 +145,9 @@ static struct lp_struct lp_table[LP_NO];
 static int port_num[LP_NO];
 
 static unsigned int lp_count = 0;
-static struct class *lp_class;
+static const struct class lp_class = {
+	.name = "printer",
+};
 
 #ifdef CONFIG_LP_CONSOLE
 static struct parport *console_registered;
@@ -932,7 +934,7 @@ static int lp_register(int nr, struct parport *port)
 	if (reset)
 		lp_reset(nr);
 
-	device_create(lp_class, port->dev, MKDEV(LP_MAJOR, nr), NULL,
+	device_create(&lp_class, port->dev, MKDEV(LP_MAJOR, nr), NULL,
 		      "lp%d", nr);
 
 	printk(KERN_INFO "lp%d: using %s (%s).\n", nr, port->name,
@@ -1004,7 +1006,7 @@ static void lp_detach(struct parport *port)
 		if (port_num[n] == port->number) {
 			port_num[n] = -1;
 			lp_count--;
-			device_destroy(lp_class, MKDEV(LP_MAJOR, n));
+			device_destroy(&lp_class, MKDEV(LP_MAJOR, n));
 			parport_unregister_device(lp_table[n].dev);
 		}
 	}
@@ -1049,11 +1051,9 @@ static int __init lp_init(void)
 		return -EIO;
 	}
 
-	lp_class = class_create("printer");
-	if (IS_ERR(lp_class)) {
-		err = PTR_ERR(lp_class);
+	err = class_register(&lp_class);
+	if (err)
 		goto out_reg;
-	}
 
 	if (parport_register_driver(&lp_driver)) {
 		printk(KERN_ERR "lp: unable to register with parport\n");
@@ -1072,7 +1072,7 @@ static int __init lp_init(void)
 	return 0;
 
 out_class:
-	class_destroy(lp_class);
+	class_unregister(&lp_class);
 out_reg:
 	unregister_chrdev(LP_MAJOR, "lp");
 	return err;
@@ -1115,7 +1115,7 @@ static void lp_cleanup_module(void)
 #endif
 
 	unregister_chrdev(LP_MAJOR, "lp");
-	class_destroy(lp_class);
+	class_unregister(&lp_class);
 }
 
 __setup("lp=", lp_setup);
-- 
2.41.0

[PATCH 4/9] /dev/mem: make mem_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the mem_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/mem.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index f494d31f2b98..2f944522f18f 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -753,20 +753,23 @@ static char *mem_devnode(const struct device *dev, umode_t *mode)
 	return NULL;
 }
 
-static struct class *mem_class;
+static const struct class mem_class = {
+	.name		= "mem",
+	.devnode	= mem_devnode,
+};
 
 static int __init chr_dev_init(void)
 {
+	int retval;
 	int minor;
 
 	if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
 		printk("unable to get major %d for memory devs\n", MEM_MAJOR);
 
-	mem_class = class_create("mem");
-	if (IS_ERR(mem_class))
-		return PTR_ERR(mem_class);
+	retval = class_register(&mem_class);
+	if (retval)
+		return retval;
 
-	mem_class->devnode = mem_devnode;
 	for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
 		if (!devlist[minor].name)
 			continue;
@@ -777,7 +780,7 @@ static int __init chr_dev_init(void)
 		if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
 			continue;
 
-		device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
+		device_create(&mem_class, NULL, MKDEV(MEM_MAJOR, minor),
 			      NULL, devlist[minor].name);
 	}
 
-- 
2.41.0

[PATCH 5/9] char: misc: make misc_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the misc_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/misc.c | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 1c44c29a666e..541edc26ec89 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -168,7 +168,21 @@ static int misc_open(struct inode *inode, struct file *file)
 	return err;
 }
 
-static struct class *misc_class;
+static char *misc_devnode(const struct device *dev, umode_t *mode)
+{
+	const struct miscdevice *c = dev_get_drvdata(dev);
+
+	if (mode && c->mode)
+		*mode = c->mode;
+	if (c->nodename)
+		return kstrdup(c->nodename, GFP_KERNEL);
+	return NULL;
+}
+
+static const struct class misc_class = {
+	.name		= "misc",
+	.devnode	= misc_devnode,
+};
 
 static const struct file_operations misc_fops = {
 	.owner		= THIS_MODULE,
@@ -226,7 +240,7 @@ int misc_register(struct miscdevice *misc)
 	dev = MKDEV(MISC_MAJOR, misc->minor);
 
 	misc->this_device =
-		device_create_with_groups(misc_class, misc->parent, dev,
+		device_create_with_groups(&misc_class, misc->parent, dev,
 					  misc, misc->groups, "%s", misc->name);
 	if (IS_ERR(misc->this_device)) {
 		if (is_dynamic) {
@@ -263,43 +277,30 @@ void misc_deregister(struct miscdevice *misc)
 
 	mutex_lock(&misc_mtx);
 	list_del(&misc->list);
-	device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
+	device_destroy(&misc_class, MKDEV(MISC_MAJOR, misc->minor));
 	misc_minor_free(misc->minor);
 	mutex_unlock(&misc_mtx);
 }
 EXPORT_SYMBOL(misc_deregister);
 
-static char *misc_devnode(const struct device *dev, umode_t *mode)
-{
-	const struct miscdevice *c = dev_get_drvdata(dev);
-
-	if (mode && c->mode)
-		*mode = c->mode;
-	if (c->nodename)
-		return kstrdup(c->nodename, GFP_KERNEL);
-	return NULL;
-}
-
 static int __init misc_init(void)
 {
 	int err;
 	struct proc_dir_entry *ret;
 
 	ret = proc_create_seq("misc", 0, NULL, &misc_seq_ops);
-	misc_class = class_create("misc");
-	err = PTR_ERR(misc_class);
-	if (IS_ERR(misc_class))
+	err = class_register(&misc_class);
+	if (err)
 		goto fail_remove;
 
 	err = -EIO;
 	if (register_chrdev(MISC_MAJOR, "misc", &misc_fops))
 		goto fail_printk;
-	misc_class->devnode = misc_devnode;
 	return 0;
 
 fail_printk:
 	pr_err("unable to get major %d for misc devices\n", MISC_MAJOR);
-	class_destroy(misc_class);
+	class_unregister(&misc_class);
 fail_remove:
 	if (ret)
 		remove_proc_entry("misc", NULL);
-- 
2.41.0

[PATCH 6/9] ppdev: make ppdev_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the ppdev_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/ppdev.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 81ed58157b15..4c188e9e477c 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -773,7 +773,9 @@ static __poll_t pp_poll(struct file *file, poll_table *wait)
 	return mask;
 }
 
-static struct class *ppdev_class;
+static const struct class ppdev_class = {
+	.name = CHRDEV,
+};
 
 static const struct file_operations pp_fops = {
 	.owner		= THIS_MODULE,
@@ -794,7 +796,7 @@ static void pp_attach(struct parport *port)
 	if (devices[port->number])
 		return;
 
-	ret = device_create(ppdev_class, port->dev,
+	ret = device_create(&ppdev_class, port->dev,
 			    MKDEV(PP_MAJOR, port->number), NULL,
 			    "parport%d", port->number);
 	if (IS_ERR(ret)) {
@@ -810,7 +812,7 @@ static void pp_detach(struct parport *port)
 	if (!devices[port->number])
 		return;
 
-	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
+	device_destroy(&ppdev_class, MKDEV(PP_MAJOR, port->number));
 	devices[port->number] = NULL;
 }
 
@@ -841,11 +843,10 @@ static int __init ppdev_init(void)
 		pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
 		return -EIO;
 	}
-	ppdev_class = class_create(CHRDEV);
-	if (IS_ERR(ppdev_class)) {
-		err = PTR_ERR(ppdev_class);
+	err = class_register(&ppdev_class);
+	if (err)
 		goto out_chrdev;
-	}
+
 	err = parport_register_driver(&pp_driver);
 	if (err < 0) {
 		pr_warn(CHRDEV ": unable to register with parport\n");
@@ -856,7 +857,7 @@ static int __init ppdev_init(void)
 	goto out;
 
 out_class:
-	class_destroy(ppdev_class);
+	class_unregister(&ppdev_class);
 out_chrdev:
 	unregister_chrdev(PP_MAJOR, CHRDEV);
 out:
@@ -867,7 +868,7 @@ static void __exit ppdev_cleanup(void)
 {
 	/* Clean up all parport stuff */
 	parport_unregister_driver(&pp_driver);
-	class_destroy(ppdev_class);
+	class_unregister(&ppdev_class);
 	unregister_chrdev(PP_MAJOR, CHRDEV);
 }
 
-- 
2.41.0

[PATCH 7/9] virtio_console: make port class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, remove the class field of the ports_driver_data structure and
create the port_class static class structure declared at build time
which places it into read-only memory, instead of having it to be
dynamically allocated at load time.

Cc: Amit Shah <amit@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: virtualization@lists.linux-foundation.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/virtio_console.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index b65c809a4e97..1f8da0a71ce9 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -40,9 +40,6 @@
  * across multiple devices and multiple ports per device.
  */
 struct ports_driver_data {
-	/* Used for registering chardevs */
-	struct class *class;
-
 	/* Used for exporting per-port information to debugfs */
 	struct dentry *debugfs_dir;
 
@@ -55,6 +52,10 @@ struct ports_driver_data {
 
 static struct ports_driver_data pdrvdata;
 
+static const struct class port_class = {
+	.name = "virtio-ports",
+};
+
 static DEFINE_SPINLOCK(pdrvdata_lock);
 static DECLARE_COMPLETION(early_console_added);
 
@@ -1399,7 +1400,7 @@ static int add_port(struct ports_device *portdev, u32 id)
 			"Error %d adding cdev for port %u\n", err, id);
 		goto free_cdev;
 	}
-	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
+	port->dev = device_create(&port_class, &port->portdev->vdev->dev,
 				  devt, port, "vport%up%u",
 				  port->portdev->vdev->index, id);
 	if (IS_ERR(port->dev)) {
@@ -1465,7 +1466,7 @@ static int add_port(struct ports_device *portdev, u32 id)
 
 free_inbufs:
 free_device:
-	device_destroy(pdrvdata.class, port->dev->devt);
+	device_destroy(&port_class, port->dev->devt);
 free_cdev:
 	cdev_del(port->cdev);
 free_port:
@@ -1540,7 +1541,7 @@ static void unplug_port(struct port *port)
 	port->portdev = NULL;
 
 	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
-	device_destroy(pdrvdata.class, port->dev->devt);
+	device_destroy(&port_class, port->dev->devt);
 	cdev_del(port->cdev);
 
 	debugfs_remove(port->debugfs_file);
@@ -2244,12 +2245,9 @@ static int __init virtio_console_init(void)
 {
 	int err;
 
-	pdrvdata.class = class_create("virtio-ports");
-	if (IS_ERR(pdrvdata.class)) {
-		err = PTR_ERR(pdrvdata.class);
-		pr_err("Error %d creating virtio-ports class\n", err);
+	err = class_register(&port_class);
+	if (err)
 		return err;
-	}
 
 	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
 	INIT_LIST_HEAD(&pdrvdata.consoles);
@@ -2271,7 +2269,7 @@ static int __init virtio_console_init(void)
 	unregister_virtio_driver(&virtio_console);
 free:
 	debugfs_remove_recursive(pdrvdata.debugfs_dir);
-	class_destroy(pdrvdata.class);
+	class_unregister(&port_class);
 	return err;
 }
 
@@ -2282,7 +2280,7 @@ static void __exit virtio_console_fini(void)
 	unregister_virtio_driver(&virtio_console);
 	unregister_virtio_driver(&virtio_rproc_serial);
 
-	class_destroy(pdrvdata.class);
+	class_unregister(&port_class);
 	debugfs_remove_recursive(pdrvdata.debugfs_dir);
 }
 module_init(virtio_console_init);
-- 
2.41.0

[PATCH 8/9] xilinx_hwicap: make icap_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the icap_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Simek <michal.simek@amd.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/xilinx_hwicap/xilinx_hwicap.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index a46f637da959..527153313a30 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -113,7 +113,9 @@ static DEFINE_MUTEX(hwicap_mutex);
 static bool probed_devices[HWICAP_DEVICES];
 static struct mutex icap_sem;
 
-static struct class *icap_class;
+static const struct class icap_class = {
+	.name = "xilinx_config",
+};
 
 #define UNIMPLEMENTED 0xFFFF
 
@@ -687,7 +689,7 @@ static int hwicap_setup(struct device *dev, int id,
 		goto failed3;
 	}
 
-	device_create(icap_class, dev, devt, NULL, "%s%d", DRIVER_NAME, id);
+	device_create(&icap_class, dev, devt, NULL, "%s%d", DRIVER_NAME, id);
 	return 0;		/* success */
 
  failed3:
@@ -730,7 +732,7 @@ static int hwicap_remove(struct device *dev)
 	if (!drvdata)
 		return 0;
 
-	device_destroy(icap_class, drvdata->devt);
+	device_destroy(&icap_class, drvdata->devt);
 	cdev_del(&drvdata->cdev);
 	iounmap(drvdata->base_address);
 	release_mem_region(drvdata->mem_start, drvdata->mem_size);
@@ -856,7 +858,9 @@ static int __init hwicap_module_init(void)
 	dev_t devt;
 	int retval;
 
-	icap_class = class_create("xilinx_config");
+	retval = class_register(&icap_class);
+	if (retval)
+		return retval;
 	mutex_init(&icap_sem);
 
 	devt = MKDEV(XHWICAP_MAJOR, XHWICAP_MINOR);
@@ -882,7 +886,7 @@ static void __exit hwicap_module_cleanup(void)
 {
 	dev_t devt = MKDEV(XHWICAP_MAJOR, XHWICAP_MINOR);
 
-	class_destroy(icap_class);
+	class_unregister(&icap_class);
 
 	platform_driver_unregister(&hwicap_platform_driver);
 
-- 
2.41.0

[PATCH 9/9] char: xillybus: make xillybus_class a static const structure

[Greg Kroah-Hartman]

From: Ivan Orlov <ivan.orlov0322@gmail.com>

Now that the driver core allows for struct class to be in read-only
memory, move the xillybus_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Eli Billauer <eli.billauer@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/xillybus/xillybus_class.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
index 89926fe9d813..c92a628e389e 100644
--- a/drivers/char/xillybus/xillybus_class.c
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -23,7 +23,9 @@ MODULE_LICENSE("GPL v2");
 
 static DEFINE_MUTEX(unit_mutex);
 static LIST_HEAD(unit_list);
-static struct class *xillybus_class;
+static const struct class xillybus_class = {
+	.name = "xillybus",
+};
 
 #define UNITNAMELEN 16
 
@@ -121,7 +123,7 @@ int xillybus_init_chrdev(struct device *dev,
 		len -= namelen + 1;
 		idt += namelen + 1;
 
-		device = device_create(xillybus_class,
+		device = device_create(&xillybus_class,
 				       NULL,
 				       MKDEV(unit->major,
 					     i + unit->lowest_minor),
@@ -152,7 +154,7 @@ int xillybus_init_chrdev(struct device *dev,
 
 unroll_device_create:
 	for (i--; i >= 0; i--)
-		device_destroy(xillybus_class, MKDEV(unit->major,
+		device_destroy(&xillybus_class, MKDEV(unit->major,
 						     i + unit->lowest_minor));
 
 	cdev_del(unit->cdev);
@@ -193,7 +195,7 @@ void xillybus_cleanup_chrdev(void *private_data,
 	for (minor = unit->lowest_minor;
 	     minor < (unit->lowest_minor + unit->num_nodes);
 	     minor++)
-		device_destroy(xillybus_class, MKDEV(unit->major, minor));
+		device_destroy(&xillybus_class, MKDEV(unit->major, minor));
 
 	cdev_del(unit->cdev);
 
@@ -242,19 +244,12 @@ EXPORT_SYMBOL(xillybus_find_inode);
 
 static int __init xillybus_class_init(void)
 {
-	xillybus_class = class_create("xillybus");
-
-	if (IS_ERR(xillybus_class)) {
-		pr_warn("Failed to register xillybus class\n");
-
-		return PTR_ERR(xillybus_class);
-	}
-	return 0;
+	return class_register(&xillybus_class);
 }
 
 static void __exit xillybus_class_exit(void)
 {
-	class_destroy(xillybus_class);
+	class_unregister(&xillybus_class);
 }
 
 module_init(xillybus_class_init);
-- 
2.41.0

Re: [PATCH 9/9] char: xillybus: make xillybus_class a static const structure

[Eli Billauer]

This is fine with me.

Thanks,
    Eli

Acked-by: Eli Billauer <eli.billauer@gmail.com>