[PATCH] ocxl: make ocxl_class constant

[PATCH] ocxl: make ocxl_class constant

[Greg Kroah-Hartman]

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: Frederic Barrat <fbarrat@linux.ibm.com>
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/misc/ocxl/file.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 6e63f060e4cc..ac69b7f361f5 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -14,7 +14,6 @@
 #define OCXL_NUM_MINORS 256 /* Total to reserve */
 
 static dev_t ocxl_dev;
-static struct class *ocxl_class;
 static DEFINE_MUTEX(minors_idr_lock);
 static struct idr minors_idr;
 
@@ -509,6 +508,16 @@ static void ocxl_file_make_invisible(struct ocxl_file_info *info)
 	cdev_del(&info->cdev);
 }
 
+static char *ocxl_devnode(const struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
+}
+
+static const struct class ocxl_class = {
+	.name =		"ocxl",
+	.devnode =	ocxl_devnode,
+};
+
 int ocxl_file_register_afu(struct ocxl_afu *afu)
 {
 	int minor;
@@ -529,7 +538,7 @@ int ocxl_file_register_afu(struct ocxl_afu *afu)
 
 	info->dev.parent = &fn->dev;
 	info->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
-	info->dev.class = ocxl_class;
+	info->dev.class = &ocxl_class;
 	info->dev.release = info_release;
 
 	info->afu = afu;
@@ -584,11 +593,6 @@ void ocxl_file_unregister_afu(struct ocxl_afu *afu)
 	device_unregister(&info->dev);
 }
 
-static char *ocxl_devnode(const struct device *dev, umode_t *mode)
-{
-	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
-}
-
 int ocxl_file_init(void)
 {
 	int rc;
@@ -601,20 +605,19 @@ int ocxl_file_init(void)
 		return rc;
 	}
 
-	ocxl_class = class_create("ocxl");
-	if (IS_ERR(ocxl_class)) {
+	rc = class_register(&ocxl_class);
+	if (rc) {
 		pr_err("Unable to create ocxl class\n");
 		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
-		return PTR_ERR(ocxl_class);
+		return rc;
 	}
 
-	ocxl_class->devnode = ocxl_devnode;
 	return 0;
 }
 
 void ocxl_file_exit(void)
 {
-	class_destroy(ocxl_class);
+	class_unregister(&ocxl_class);
 	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
 	idr_destroy(&minors_idr);
 }
-- 
2.42.0

Re: [PATCH] ocxl: make ocxl_class constant

[Frederic Barrat]

On 24/10/2023 13:49, Greg Kroah-Hartman wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, we should make all 'class' structures declared at build time
> placing them into read-only memory, instead of having to be dynamically
> allocated at runtime.
> 
> Cc: Frederic Barrat <fbarrat@linux.ibm.com>
> Cc: Andrew Donnellan <ajd@linux.ibm.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linuxppc-dev@lists.ozlabs.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---

Thanks!

Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>

   Fred


>   drivers/misc/ocxl/file.c | 27 +++++++++++++++------------
>   1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
> index 6e63f060e4cc..ac69b7f361f5 100644
> --- a/drivers/misc/ocxl/file.c
> +++ b/drivers/misc/ocxl/file.c
> @@ -14,7 +14,6 @@
>   #define OCXL_NUM_MINORS 256 /* Total to reserve */
>   
>   static dev_t ocxl_dev;
> -static struct class *ocxl_class;
>   static DEFINE_MUTEX(minors_idr_lock);
>   static struct idr minors_idr;
>   
> @@ -509,6 +508,16 @@ static void ocxl_file_make_invisible(struct ocxl_file_info *info)
>   	cdev_del(&info->cdev);
>   }
>   
> +static char *ocxl_devnode(const struct device *dev, umode_t *mode)
> +{
> +	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
> +}
> +
> +static const struct class ocxl_class = {
> +	.name =		"ocxl",
> +	.devnode =	ocxl_devnode,
> +};
> +
>   int ocxl_file_register_afu(struct ocxl_afu *afu)
>   {
>   	int minor;
> @@ -529,7 +538,7 @@ int ocxl_file_register_afu(struct ocxl_afu *afu)
>   
>   	info->dev.parent = &fn->dev;
>   	info->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
> -	info->dev.class = ocxl_class;
> +	info->dev.class = &ocxl_class;
>   	info->dev.release = info_release;
>   
>   	info->afu = afu;
> @@ -584,11 +593,6 @@ void ocxl_file_unregister_afu(struct ocxl_afu *afu)
>   	device_unregister(&info->dev);
>   }
>   
> -static char *ocxl_devnode(const struct device *dev, umode_t *mode)
> -{
> -	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
> -}
> -
>   int ocxl_file_init(void)
>   {
>   	int rc;
> @@ -601,20 +605,19 @@ int ocxl_file_init(void)
>   		return rc;
>   	}
>   
> -	ocxl_class = class_create("ocxl");
> -	if (IS_ERR(ocxl_class)) {
> +	rc = class_register(&ocxl_class);
> +	if (rc) {
>   		pr_err("Unable to create ocxl class\n");
>   		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
> -		return PTR_ERR(ocxl_class);
> +		return rc;
>   	}
>   
> -	ocxl_class->devnode = ocxl_devnode;
>   	return 0;
>   }
>   
>   void ocxl_file_exit(void)
>   {
> -	class_destroy(ocxl_class);
> +	class_unregister(&ocxl_class);
>   	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
>   	idr_destroy(&minors_idr);
>   }