2023-10-24 11:48:58

by Greg Kroah-Hartman

Subject: [PATCH] cxl: make cxl_class constant

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 <[email protected]>
Cc: Andrew Donnellan <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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

2023-10-25 08:17:29

by Frederic Barrat

Subject: Re: [PATCH] cxl: make cxl_class constant

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 <[email protected]>
> Cc: Andrew Donnellan <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: [email protected]
> Signed-off-by: Greg Kroah-Hartman <[email protected]>
> ---

Thanks!
Acked-by: Frederic Barrat <[email protected]>

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);
> }

2023-10-25 09:09:11

by Greg Kroah-Hartman

Subject: Re: [PATCH] cxl: make cxl_class constant

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 <[email protected]>
> > Cc: Andrew Donnellan <[email protected]>
> > Cc: Arnd Bergmann <[email protected]>
> > Cc: [email protected]
> > Signed-off-by: Greg Kroah-Hartman <[email protected]>
> > ---
>
> Thanks!
> Acked-by: Frederic Barrat <[email protected]>

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

greg k-h

2023-10-27 10:47:34

by Michael Ellerman

Subject: Re: [PATCH] cxl: make cxl_class constant

Greg Kroah-Hartman <[email protected]> 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 <[email protected]>
>> > Cc: Andrew Donnellan <[email protected]>
>> > Cc: Arnd Bergmann <[email protected]>
>> > Cc: [email protected]
>> > Signed-off-by: Greg Kroah-Hartman <[email protected]>
>> > ---
>>
>> Thanks!
>> Acked-by: Frederic Barrat <[email protected]>
>
> Thanks for the review of these, I'll take them through my char/misc tree
> now.

Ack.

cheers