[PATCH] cxl: make cxl_class constant

[PATCH] cxl: make cxl_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/cxl/file.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 144d1f2d78ce..012e11b959bc 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -38,8 +38,6 @@
 
 static dev_t cxl_dev;
 
-static struct class *cxl_class;
-
 static int __afu_open(struct inode *inode, struct file *file, bool master)
 {
 	struct cxl *adapter;
@@ -559,7 +557,10 @@ static char *cxl_devnode(const struct device *dev, umode_t *mode)
 	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 }
 
-extern struct class *cxl_class;
+static const struct class cxl_class = {
+	.name =		"cxl",
+	.devnode =	cxl_devnode,
+};
 
 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 			   struct device **chardev, char *postfix, char *desc,
@@ -575,7 +576,7 @@ static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 		return rc;
 	}
 
-	dev = device_create(cxl_class, &afu->dev, devt, afu,
+	dev = device_create(&cxl_class, &afu->dev, devt, afu,
 			"afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 	if (IS_ERR(dev)) {
 		rc = PTR_ERR(dev);
@@ -633,14 +634,14 @@ void cxl_chardev_afu_remove(struct cxl_afu *afu)
 
 int cxl_register_afu(struct cxl_afu *afu)
 {
-	afu->dev.class = cxl_class;
+	afu->dev.class = &cxl_class;
 
 	return device_register(&afu->dev);
 }
 
 int cxl_register_adapter(struct cxl *adapter)
 {
-	adapter->dev.class = cxl_class;
+	adapter->dev.class = &cxl_class;
 
 	/*
 	 * Future: When we support dynamically reprogramming the PSL & AFU we
@@ -678,13 +679,11 @@ int __init cxl_file_init(void)
 
 	pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 
-	cxl_class = class_create("cxl");
-	if (IS_ERR(cxl_class)) {
+	rc = class_register(&cxl_class);
+	if (rc) {
 		pr_err("Unable to create CXL class\n");
-		rc = PTR_ERR(cxl_class);
 		goto err;
 	}
-	cxl_class->devnode = cxl_devnode;
 
 	return 0;
 
@@ -696,5 +695,5 @@ int __init cxl_file_init(void)
 void cxl_file_exit(void)
 {
 	unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
-	class_destroy(cxl_class);
+	class_unregister(&cxl_class);
 }
-- 
2.42.0

Re: [PATCH] cxl: make cxl_class constant

[Frederic Barrat]

On 24/10/2023 13:48, 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/cxl/file.c | 21 ++++++++++-----------
>   1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
> index 144d1f2d78ce..012e11b959bc 100644
> --- a/drivers/misc/cxl/file.c
> +++ b/drivers/misc/cxl/file.c
> @@ -38,8 +38,6 @@
>   
>   static dev_t cxl_dev;
>   
> -static struct class *cxl_class;
> -
>   static int __afu_open(struct inode *inode, struct file *file, bool master)
>   {
>   	struct cxl *adapter;
> @@ -559,7 +557,10 @@ static char *cxl_devnode(const struct device *dev, umode_t *mode)
>   	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
>   }
>   
> -extern struct class *cxl_class;
> +static const struct class cxl_class = {
> +	.name =		"cxl",
> +	.devnode =	cxl_devnode,
> +};
>   
>   static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
>   			   struct device **chardev, char *postfix, char *desc,
> @@ -575,7 +576,7 @@ static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
>   		return rc;
>   	}
>   
> -	dev = device_create(cxl_class, &afu->dev, devt, afu,
> +	dev = device_create(&cxl_class, &afu->dev, devt, afu,
>   			"afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
>   	if (IS_ERR(dev)) {
>   		rc = PTR_ERR(dev);
> @@ -633,14 +634,14 @@ void cxl_chardev_afu_remove(struct cxl_afu *afu)
>   
>   int cxl_register_afu(struct cxl_afu *afu)
>   {
> -	afu->dev.class = cxl_class;
> +	afu->dev.class = &cxl_class;
>   
>   	return device_register(&afu->dev);
>   }
>   
>   int cxl_register_adapter(struct cxl *adapter)
>   {
> -	adapter->dev.class = cxl_class;
> +	adapter->dev.class = &cxl_class;
>   
>   	/*
>   	 * Future: When we support dynamically reprogramming the PSL & AFU we
> @@ -678,13 +679,11 @@ int __init cxl_file_init(void)
>   
>   	pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
>   
> -	cxl_class = class_create("cxl");
> -	if (IS_ERR(cxl_class)) {
> +	rc = class_register(&cxl_class);
> +	if (rc) {
>   		pr_err("Unable to create CXL class\n");
> -		rc = PTR_ERR(cxl_class);
>   		goto err;
>   	}
> -	cxl_class->devnode = cxl_devnode;
>   
>   	return 0;
>   
> @@ -696,5 +695,5 @@ int __init cxl_file_init(void)
>   void cxl_file_exit(void)
>   {
>   	unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
> -	class_destroy(cxl_class);
> +	class_unregister(&cxl_class);
>   }

Re: [PATCH] cxl: make cxl_class constant

[Greg Kroah-Hartman]

On Wed, Oct 25, 2023 at 10:16:55AM +0200, Frederic Barrat wrote:
> 
> 
> On 24/10/2023 13:48, 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>

Thanks for the review of these, I'll take them through my char/misc tree
now.

greg k-h

Re: [PATCH] cxl: make cxl_class constant

[Michael Ellerman]

Greg Kroah-Hartman <gregkh@linuxfoundation.org> writes:
> On Wed, Oct 25, 2023 at 10:16:55AM +0200, Frederic Barrat wrote:
>> On 24/10/2023 13:48, 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>
>
> Thanks for the review of these, I'll take them through my char/misc tree
> now.

Ack.

cheers